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The bilingual brain. Proficiency and age of acquisition of the second language
Abstract
Functional imaging methods show differences in the pattern of cerebral activation associated with the subject's native language (L1) compared with a second language (L2). In a recent PET investigation on bilingualism we showed that auditory processing of stories in L1 (Italian) engages the temporal lobes and temporoparietal cortex more extensively than L2 (English). However, in that study the Italian subjects learned L2 late and attained a fair, but not an excellent command of this language (low proficiency, late acquisition bilinguals). Thus, the different patterns of activation could be ascribed either to age of acquisition or to proficiency level. In the current study we use a similar paradigm to evaluate the effect of early and late acquisition of L2 in highly proficient bilinguals. We studied a group of Italian-English bilinguals who acquired L2 after the age of 10 years (high proficiency, late acquisition bilinguals) and a group of Spanish-Catalan bilinguals who acquired L2 before the age of 4 years (high proficiency, early acquisition bilinguals). The differing cortical responses we had observed when low proficiency volunteers listened to stories in L1 and L2 were not found in either of the high proficiency groups in this study. Several brain areas, similar to those observed for L1 in low proficiency bilinguals, were activated by L2. These findings suggest that, at least for pairs of L1 and L2 languages that are fairly close, attained proficiency is more important than age of acquisition as a determinant of the cortical representation of L2.
... Similarly, Perani et al. (1998) found evidence for differences in activation in both left and right temporal and hippocampal regions between high and low proficiency groups in a PET investigation of performance on a task involving comprehension of an entire story. Low-proficiency bilinguals showed lower activation than high-proficiency bilinguals, though both bilingual groups displayed greater activity (more blood flow) located in areas also associated with L1 (Perani et al. 1998). ...
... Similarly, Perani et al. (1998) found evidence for differences in activation in both left and right temporal and hippocampal regions between high and low proficiency groups in a PET investigation of performance on a task involving comprehension of an entire story. Low-proficiency bilinguals showed lower activation than high-proficiency bilinguals, though both bilingual groups displayed greater activity (more blood flow) located in areas also associated with L1 (Perani et al. 1998). Together, this evidence suggests that although general localization of neural speech processing may be common between monolingual and bilingual groups; levels of activation and/or diverse neural regions may also differ. ...
... The VOT overlap with Spanish-voiceless consonants may have affected their identification and recognition of these words. In sum, our results support those of Archila-Suerte et al. (2015) and Perani et al. (1998) that localization of speech perception may be similar for both monolingual and bilingual populations, yet their levels of activation differed. Early age of acquisition bilinguals in this study seemed to recruit additional areas when engaging in code-mixing, especially involving the left lateral prefrontal cortex (optode 2, left LPFC). ...
The study investigated word recognition during neural activation in monolinguals and bilinguals. We specifically examined word retrieval and blood-oxygenation changes in the prefrontal cortex during a code-mixed word recognition task. Participants completed a gating task incorporating monolingual sentences and Spanish-English code-mixed sentences while using functional near-infrared spectroscopy (fNIRS) to measure blood-oxygenation changes. Word recognition contained four phonotactic conditions: (1) voiceless initial consonants, (2) voiced initial consonants, (3) CV-tense words, and (4) CV-lax words. Bilingual speakers had word-recognition capabilities similar to monolingual speakers even when identifying English words. Word recognition outcomes suggested that prefrontal cortex functioning is similar for early age of acquisition (AOA) bilinguals and monolinguals when identifying words in both code-mixed and monolingual sentences. Monolingual speakers experienced difficulty with English-voiced consonant sounds; while bilingual speakers experienced difficulties with English-lax vowels. Results suggest that localization of speech perception may be similar for both monolingual and bilingual populations, yet levels of activation differed. Our findings suggest that this parity is due to early age of acquisition (AoA) bilinguals finding a balance of language capabilities (i.e., native-like proficiency) and that in some instances the bilingual speakers processed language in the same areas dedicated to first language processing.
... There has been a consensus among researchers that brain networks involved in L1 and L2 processing are mostly overlapping in bilingual adults with subtle accommodations to the special features of the language (Perani et al., 1998;Chee et al., 1999a;Klein et al., 1999;Chee et al., 2000;Tettamanti et al., 2002;Musso et al., 2003;Sakai et al., 2004;Perani and Abutalebi, 2005). This neuroimaging finding of great overlap between L1 and L2 is consistent with the repeated observation from behavioral studies that L1 influences the organization of L2's representations (Wu and Thierry, 2010;Costa et al., 2016), suggesting an extensive transfer from L1 to L2 (Koda, 1990;Kroll et al., 2012). ...
... A recent study further suggests that higher L2 proficiency is related to greater similarity between L1 and L2 in brain activation in Chinese-English late bilingual adults (Cao et al., 2013a). Similarly, another study found that higher proficiency is associated with greater overlap between L1 and L2 in Italian-English bilinguals (Perani et al., 1998). The proficiency effect found in the previous two studies is supportive of the convergence hypothesis proposed by Green (2003), which argues that differences between native speakers and L2 speakers disappear as L2 proficiency increases. ...
... The DSC was 0.26 in adults and 0 in children. This is consistent with the convergence hypothesis that increased proficiency in L2 is associated with greater similarity to L1 brain activation (Perani et al., 1998;Golestani et al., 2006;Stein et al., 2009;Cao et al., 2013a). A previous study found that early bilinguals showed greater similarity between L1 and L2 at the left IFG than late bilinguals (Kim et al., 1997), suggesting an AOA effect. ...
It has been documented that processing L2 and L1 engages a very similar brain network in bilingual adults. However, it is not known whether this similarity is evident in bilingual children as well or it develops with learning from children to adults. In the current study, we compared brain activation in Chinese-English bilingual children and adults during L1 and L2 processing. We found greater similarity between L1 and L2 in adults than in children, supporting the convergence hypothesis which argues that when the proficiency of L2 increases, the L2’s brain network converges to the L1’s brain network. We also found greater differences between adults and children in the brain for L2 processing than L1 processing, even though there were comparable increase in proficiency from children to adults in L1 and L2. It suggests an elongated developmental course for L2. This study provides important insights about developmental changes in the bilingual brain.
... Maybe the problem is not so much the occurrences of the subjunctive but the fact that the neurocognitive processing of the subjunctive may differ in native French and French L2 learners. One could assume that, as remarked by some EEG and fMRI studies [9,[140][141][142][143][144][145] (see [146] for a review), even if the same brain areas are recruited during L1 and L2 processing for syntactic structures, neurocognitive circuits are not the same for processing the L1 and the L2. Hence different brain neuronal correlates may be implicated in natives and L2 learners, at least at low levels of proficiency. ...
... EEG and fMRI studies demonstrated that with a high level of proficiency in L2, the same brain neuronal circuits are recruited during L1 and L2 processing. For example, Perani and colleagues [145] investigated the effect of the early and late acquisition of L2 in high and low-proficient bilinguals assessed with positron emission tomography (PET). Subjects were English-Italian bilinguals (aged between 19 to 50) who acquired English after the age of 10 years (high proficiency group, late acquisition bilinguals), Spanish-Catalan bilinguals who acquired their L2 before the age of 4 (high proficiency and early acquisition bilinguals), and a volunteer group of Italian native speakers of English, who learned English after the age of 10 at school (low proficiency group). ...
The acquisition of a second language requires the construction or reconstruction of linguistic knowledge about the new language system. Learners of a second language have to acquire the linguistic structures of the second language by constructing or reassessing their own knowledge in the light of the new one. Some of these new linguistic structures may be more or less complex to process and/or difficult to acquire. In this review, we focus on an example of linguistic complexity in French, namely, the subjunctive. Through a discussion of some selected studies on the second language acquisition of the French subjunctive, our purpose is to argue that these findings, considered from a psycholinguistic perspective, could be fruitful for further research employing neuroscience techniques, such as electroencephalography or neuroimaging in order to better understand the neurocognitive processing of this complex structure both in French native speakers and in learners of French. Hence, we aim to contribute to exploring the question of linguistic transfer in the field of second language acquisition, the typological distance/relation between L1–L2, the syntactic acquisition of complex structures in adult second language learners, and the potential contributions of electroencephalography and functional magnetic resonance imaging to the processing of the subjunctive, selected as an example of linguistic complexity that has not yet received much attention.
... Neuroimaging studies of bilinguals and polyglots have also highlighted the potential role of other variables such as degree of proficiency or level of exposure, showing that attained proficiency and possibly language exposure are more important than the age of acquisition as a determinant of the cerebral representation of languages in bilinguals/polyglots [57]. Functional neuroimaging with PET and fMRI offers us an indirect window into the complex mechanism of interaction of all these environmental factors [66], but various points should be taken into consideration: (i) the vast majority of neuroimaging studies have been performed on bilingual patients using fMRI [54,[69][70][71]; (ii) neuroscientific studies with participants who master three or more languages presently are rare [72][73][74]; (iii) notwithstanding the fact that all fMRI studies employed the same biophysical principle of BOLD signal analysis, sometimes divergent results are obtained, probably due to the heterogeneity of the tasks used during the execution of the paradigm; (iv) fMRI is a guidance tool that has yet to be validated by ESM during awake surgery [75], and therefore ESM is not only the "gold standard" technique for localizing cortico-subcortical language areas during brain tumor or epilepsy surgery, but it is also an excellent tool that helps us to understand language organization in humans [56,61]. Perani et al. (2003) [70] designed an fMRI experiment to investigate any differences in brain activation in 11 highly proficient early bilingual subjects (Spanish-Catalan) with different acquisition ages. ...
... An exception is Fernández-Coello et al. (2017) [56], who focused on how age of L2-acquisition influenced the cortical spatial organization of language in 13 polyglots. The results showed that there were no significant differences in cortical extent with respect to age of language acquisition between L1 stimulation sites (47 sites), early-L2 (50 sites), and late-L2 (70 sites), which is in agreement with other ESM studies in bilingual patients [34,36] but contrary to the findings of some fMRI studies [22,70,71] discussed above. These divergences could be explained by the higher workload needed for L2 processing, which seems to be responsible for the enhanced functional activity (fMRI) in some brain areas, e.g., the dorsolateral prefrontal cortex (DLPFC) [77]. ...
In this review, we evaluate the knowledge gained so far about the neural bases of multilingual language processing obtained mainly through imaging and electrical stimulation mapping (ESM). We attempt to answer some key questions about multilingualism in the light of recent literature evidence, such as the degree of anatomical–functional integration of two or more languages in a multilingual brain, how the age of L2-acquisition affects language organization in the human brain, or how the brain controls more than one language. Finally, we highlight the future trends in multilingual language mapping.
... Proficiency and age of acquisition of L2 have been demonstrated to influence not only behavioural aspects but also the manner in which the bilingual brain becomes activated (Perani et al., 1998). In an fMRI study, the authors employed two groups of participants to investigate the effect of early and late acquisition of L2 in highly proficient bilinguals: a) Italian-English bilinguals who acquired L2 after the age of 10 years, and b) Spanish-Catalan bilinguals who acquired L2 before the age of four years. ...
... In an fMRI study, the authors employed two groups of participants to investigate the effect of early and late acquisition of L2 in highly proficient bilinguals: a) Italian-English bilinguals who acquired L2 after the age of 10 years, and b) Spanish-Catalan bilinguals who acquired L2 before the age of four years. Perani et al. (1998) reported that 'for pairs of L1 and L2 languages that are fairly close, attained proficiency is more important than age of acquisition as a determinant of the cortical representation of L2'. ...
The chapter examines the relationship between orthography, phonology, and morphology in Turkish and what this means for Turkish-English bilingual language processing. Turkish offers a unique language medium in pitching theoretical perspectives both in linguistics and psycholinguistics against each other because of its properties. Empirical and theoretical considerations are employed from both domains in order to shed light on some of the current challenges. In line with contemporary thought, this chapter is written with the view that bilingual speakers engage a singular language or lexical system characterized by fluid and dynamic processes. Particular focus will be given to English-Turkish speaking bilinguals in the UK, which includes heritage (HL) and non-heritage language speakers. Evidence from monolingual developmental research as well as neuropsychology will be examined to confirm findings of previous studies in other European contexts, and also to raise attention to various challenges which need to be addressed across all contexts.
... The field of study examines language processing in both healthy individuals and those with language impairments using a variety of neurophysiological techniques, including brain imaging techniques (e.g., ERP, fMRI) (Roberts et al., 2018;Schiller, N., 2009). Bilinguals (people who speak two languages) activate different neural pathways than monolinguals (people who speak only one language), according to fMRI ( functional magnetic resonance imaging) research, suggesting that learning a second language depends on different cognitive processes (Perani et al., 1998). According to ERP (event-related potential) research, those who have SLI show delayed neural responses to grammatical structures, which may indicate that their brains perceive syntax differently than individuals who are typically developing (Weismer et al., 2005). ...
Language disorders such as dyslexia, Specific Language Impairment (SLI), and aphasia disrupt the natural acquisition and use of language, posing significant challenges for learners and educators. This thesis examines the neurological underpinnings of these disorders, drawing on neurolinguistic theories (e.g., modular, connectionist, and dual-route models) and neuroimaging evidence (fMRI, ERP) to elucidate their impact on first (L1) and second language (L2) learning. Key findings highlight the roles of Broca's area, Wernicke's area, and the arcuate fasciculus in language processing, with damage to these regions leading to distinct deficits in production, comprehension, or repetition. The study further explores how these disorders manifest in L2 acquisition, emphasizing the need for adaptive pedagogical strategies.
... However, this period may vary depending on the environment of the growing child, making the definition of early bilingualism as "bilingual from birth or a very young age" (Gold, 2017;De Houwer, 2012) little confusing. For instance, Perani and colleagues evaluated differences between early and late bilingualism and their EB group consisted of participants who acquired their second language before the age of 4 years and their LB group after the age of 10 years (Perani et al., 1998), whereas some studies determined early-late bilingualism cutoff age as 10 years (Bak, Vega-Mendoza, & Sorace, 2014;Luk et al., 2011). However, the cutoff age for late bilingualism is not always clear-cut. ...
Language is a sophisticated cognitive skill that relies on the coordinated activity of cerebral cortex. Acquiring a second language creates intricate modifications in brain connectivity. Although considerable studies have evaluated the impact of second language acquisition on brain networks in adulthood, the results regarding the ultimate form of adaptive plasticity remain inconsistent within the adult population. Furthermore, due to the assumption that subcortical regions are not significantly involved in language-related tasks, the thalamus has rarely been analyzed in relation to other language-relevant cortical regions. Given these limitations, we aimed to evaluate the functional connectivity and volume modifications of thalamic subfields using magnetic resonance imaging (MRI) modalities following the acquisition of a second language. Structural MRI and fMRI data from 51 participants were collected from the OpenNeuro database. The participants were divided into three groups: monolingual (ML), early bilingual (EB), and late bilingual (LB). The EB group consisted of individuals proficient in both English and Spanish, with exposure to these languages before the age of 10 years. The LB group consisted of individuals proficient in both English and Spanish, but with exposure to these languages after the age of 14 years. The ML group included participants proficient only in English. Our results revealed that the ML group exhibited increased functional connectivity in all thalamic subfields (anterior, intralaminar-medial, lateral, ventral, and pulvinar) compared with the EB and LB groups. In addition, a significantly decreased volume of the left suprageniculate nucleus was found in the bilingual groups compared with the ML group. This study provides valuable evidence suggesting that acquiring a second language may be protective against dementia, due to its high plasticity potential, which acts synergistically with cognitive functions to slow the degenerative process.
... Using a variety of neuroscience methods, such as functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs), researchers have investigated functional and structural brain changes induced by L2 learning (e.g., Wong et al., 2007;Li et al., 2014;Pliatsikas et al., 2015; for a review, van Hell, 2023). Key modulators, such as L2 age of acquisition (e.g., Perani et al., 1998;Hernandez and Li, 2007), L2 proficiency (DeLuca et al., 2019;Wang et al., 2020), L2 immersion experience (e.g., Stein et al., 2014), and language learning duration (Berken et al., 2016), have also been investigated. Nevertheless, our understanding of L2-learningrelated neuroplasticity and individual differences is still in its infancy compared to L1 acquisition. ...
... proficiency (Perani, 1998), have been shown to significantly impact the organisation of the neural systems that support written language processing. Therefore, for our cohort, who mostly began acquiring French relatively late and as an L2, the underlying neural architecture is likely somewhat different from that underlying developing L1 readers or L2 learners in WEIRD contexts. ...
... Thus, cognitive bilingualism remains a mosaic in which psychological approaches and linguistic realities are pieced together (see Gullifer &Titone's language entropy, 2020, andAbutalebi's adaptive control, 2013). The picture that presents itself as yet lacks full coherence due to an absence of a clear description of all influential and decisive factors, which may modulate or even cancel out each other (e.g., proficiency vs. AoA in Perani et al. 1998) and influence distinct brain networks (Nichols & Joanisse, 2016). Nevertheless, there is evidence that bilingual experience can reshape brain structure and change brain connectivity (DeLuca et al., 2020;Pliatsikas et al., 2017). ...
In this chapter, we consider different definitions of bilingualism, underscoring the reality that there are various aspects which should be taken into account when investigating bilingualism, particularly when designing studies and choosing participants. Bilingualism is a complex construct and should be viewed on a continuum. Crucially, many key details about bilinguals’ backgrounds need to be reported in studies to make results comparable and clearly linkable to the specific study sample. Relative proficiency level seems to be the most influential factor, but it is by no means the only factor relevant for studying bilingualism. Rather, individual differences and their variability, dynamically related dimensions and their interaction over time, speech environment and their changes, language use habits, socioeconomic background, and so on have been reported to influence language processing and even brain function to some extent.
... The age of acquisition and language use differentially influence the engagement of the language network in bilinguals as well (e.g., Cargnelutti et al., 2019;Jasinska & Petitto, 2013;Pallier et al., 2003;Perani et al., 1998;Sulpizio et al., 2020;Sun et al., 2023;van Heuven & Dijkstra, 2010). Neurotypical monolingual adults often engage the left inferior frontal cortex, temporal, and inferior parietal regions during sentence processing tasks (for reviews, see Hagoort, 2019;Hagoort & Indefrey, 2014). ...
Purpose
The aim of this study was to examine the effects of early bilingual exposure on Spanish–English bilingual children's neural organization of English morphosyntactic structures. This study examines how children's age and language experiences are related to morphosyntactic processing at the neural level.
Method
Eighty-one children (ages 6–11 years) completed an auditory sentence judgment task during functional near-infrared spectroscopy neuroimaging. The measure tapped into children's processing of early-acquired (present progressive –ing) and later-acquired (past tense –ed and third-person singular –s) English morphosyntactic structures, the primary language of academic instruction.
Results
We observed effects of syntactic structure and age. Early-acquired morphemic structures elicited activation in the left inferior frontal gyrus, while the later-acquired structures elicited additional activations in the left middle temporal gyrus and superior temporal gyrus (STG). Younger children had a more distributed neural response, whereas older children had a more focal neural response. Finally, there was a trending association between children's English language use and left STG activation for later-acquired structures.
Conclusion
The findings inform theories of language and brain development by highlighting the mechanisms by which age and language experiences influence bilingual children's neural architecture for morphosyntactic processing.
... Some previous studies have designed diverse tasks to explore the neural correlates of executive control in bilinguals. The findings revealed that bilinguals demonstrated similar activation of brain regions at both word and sentence levels during task performance regardless of whether participants were using their first or L2 [12,13]. Green et al. found that the left inferior frontal gyrus and anterior cingulate cortex were activated in bilinguals during language switching by using a color-shape switching task [14]. ...
Bilingualism is known to enhance cognitive function and flexibility of the brain. However, it is not clear how bilingual experience affects the time-varying functional network and whether these changes depend on the age of bilingual onset. This study intended to investigate the bilingual-related dynamic functional connectivity (dFC) based on the resting-state functional magnetic resonance images, including 23 early bilinguals (EBs), 30 late bilinguals (LBs), and 31 English monolinguals. The analysis identified two dFC states, and LBs showed more transitions between these states than monolinguals. Moreover, more frequent left–right switches were found in functional laterality in prefrontal, lateral temporal, lateral occipital, and inferior parietal cortices in EBs compared with LB and monolingual cohorts, and the laterality changes in the anterior superior temporal cortex were negatively correlated with L2 proficiency. These findings highlight how the age of L2 acquisition affects cortico-cortical dFC pattern and provide insight into the neural mechanisms of bilingualism.
... That is, it has been shown that irrespective of AoA, subcortical and neural activation dissimilarities were found between low-and high-proficiency learners (Abutalebi & Green, 2007;Chee et al., 1999;Klein et al., 1995;Perani et al., 1996;Perani et al., 1998;Pillai et al., 2003). ...
It is widely documented that L2 learners, particularly late learners, find difficulties in acquiring and appropriately using L2 in a comparable proficiency to L1 (S. Segalowitz et al., 1998). It has further been documented that even advanced learners may face difficulties in producing target-like word combinations and phrases (Yusuf, 2017). To account for these difficulties and to facilitate L2 acquisition, this research proposes a neuroeducational model (LIRRA) for improving L2 proficiency in late learners. The neuroeducational model rests primarily on five key brain-adaptive features as evidenced in the literature viz. exposure to L2 lexical phrases, implicit learning of L2, reiterative exposure to L2 phrases, a rewarding/motivating learning environment, and an attentional-stimulating learning setting. From this perspective, this paper first introduces neuroeducation; then sheds light on some of the misconceptions pertaining to L2 learning particularly for late learners. Following this, the paper provides in-depth illustration of the brain-adaptive features and provides the rationale behind proposing a neuroeducational model on the premise thereof. Furthermore, this paper argues in support of the integration of this neuroeducational model in neuroeducation programs for L2 acquisition in late learners and provides recommendations therein.
... Some previous studies have designed diverse tasks to explore the neural correlates of executive control in bilinguals. The findings revealed that bilinguals demonstrated similar activation of brain regions at both word and sentence levels during task performance regardless of whether participants were using their first or L2 [12,13]. Green et al. found that the left inferior frontal gyrus and anterior cingulate cortex were activated in bilinguals during language switching by using a color-shape switching task [14]. ...
... Another processing difference that has been noted between early and late bilinguals is that the latter group required higher levels of neural activation to complete L2 than L1 tasks, whereas early bilinguals showed no activation differences between their two languages (Saur et al., 2009). However, parallel lines of research have suggested that it is not the age of onset but the attained proficiency in the L2 that is a key determinant of neural processing patterns (e.g., Perani et al., 1998;Pelham and Abrams, 2014, early AOA: around 4 and 3 years, late AOA: around 11 and 10 years, respectively). ...
Previous research on the processing of language embedded in a rich visual context has revealed the strong effect that a recently viewed action event has on language comprehension. It has been shown that listeners are more likely to view the target object of a recently performed event than look at the target object of a plausible future event during sentence utterance, regardless of the tense cue. In the current visual-world eye-tracking experiments, we tested the strength of the recently observed visual context with a group of English monolingual and two groups of English–French early and late bilingual speakers. By comparing these different groups, we examined whether bilingual speakers, as a consequence of greater cognitive flexibility when integrating visual context and language information, show early anticipatory eye-movements toward the target object. We further asked whether early and late bilinguals show differences in their processing. The findings of the three eye-tracking experiments revealed an overall preference for the recently seen event. However, as a result of the early provision of tense cue, this preference was quickly diminished in all three groups. Moreover, the bilingual groups showed an earlier decrease in reliance on the recently seen event compared to monolingual speakers and the early bilinguals showed anticipatory eye-movements toward the plausible future event target. Furthermore, a post-experimental memory test revealed that the bilingual groups recalled the future events marginally better than the recent events, whereas the reverse was found in the monolingual groups.
... Thus, cognitive bilingualism remains a mosaic in which psychological approaches and linguistic realities are pieced together (see Gullifer &Titone's language entropy, 2020, andAbutalebi's adaptive control, 2013). The picture that presents itself as yet lacks full coherence due to an absence of a clear description of all influential and decisive factors, which may modulate or even cancel out each other (e.g., proficiency vs. AoA in Perani et al. 1998) and influence distinct brain networks (Nichols & Joanisse, 2016). Nevertheless, there is evidence that bilingual experience can reshape brain structure and change brain connectivity (DeLuca et al., 2020;Pliatsikas et al., 2017). ...
In this chapter, we use the term cognitive bilingualism to refer to a merge of two research traditions: i) the psycholinguistics of bilingualism (i.e., models and theories that try to describe in psycholinguistic thinking and terms how bilingualism works); and ii) work on the psychological aspects of language, in particular of bilingualism and specifically of effects and consequences of bilingualism on cognition (i.e., cognitive processes and development). The chapter provides an overview of the most prominent and empirically well-supported theories and models of cognitive bilingualism. In doing so, the cognitive control required for bilingual language processing in production and perception will be briefly reviewed as well as the impact of using two or more languages on cognitive development. Finally, the ongoing debate on the benefits of bilingualism on higher cognition will be outlined and discussed.
... The question of whether a multilingual model induces a shared representational space where abstract cross-linguistic regularities are encoded through a common set of parameters is remindful of the debate on the neural underpinning of linguistic knowledge in multilingual individuals (see Dhar and Bisazza [2021] for similar considerations). In particular, the problem is reminiscent of the question of whether the neural resources allocated to different languages in a multilingual brain overlap (at least partially, see Perani et al. 1998;Abutalebi, Cappa, and Perani 2001;Perani and Abutalebi 2005;Green 2008) or involve functionally independent neural populations (Kim et al. 1997;Tham et al. 2005;Tan et al. 2011;Xu et al. 2017). If we consider the possibility of looking at artificial neural networks as a different "species" (Cummins and Schwarz 1988;McCloskey 1991), in a fashion that reminds us of the study of animal models, the study of the representations produced by these networks might offer novel insights into the space of possible solutions to the cognitive question mentioned above. ...
Massively multilingual models such as mBERT and XLM-R are increasingly valued in Natural Language Processing research and applications, due to their ability to tackle the uneven distribution of resources available for different languages. The models’ ability to process multiple languages relying on a shared set of parameters raises the question of whether the grammatical knowledge they extracted during pre-training can be considered as a data-driven cross-lingual grammar. The present work studies the inner workings of mBERT and XLM-R in order to test the cross-lingual consistency of the individual neural units that respond to a precise syntactic phenomenon, that is, number agreement, in five languages (English, German, French, Hebrew, Russian). We found that there is a significant overlap in the latent dimensions that encode agreement across the languages we considered. This overlap is larger (a) for long- vis-à-vis short-distance agreement and (b) when considering XLM-R as compared to mBERT, and peaks in the intermediate layers of the network. We further show that a small set of syntax-sensitive neurons can capture agreement violations across languages; however, their contribution is not decisive in agreement processing.
... First, consistent with the convergence hypothesis (Green, 2003), L1 and L2 processing share cognitive mechanisms and neural substrates for speech perception, semantic representation, and syntactic processing (Abutalebi, 2008;Costa and Sebastian-Galles, 2014;Illes et al., 1999;Kotz, 2009;Perani et al., 1998;Sebastian et al., 2011). Second, L2 proficiency or ability has been associated with cognitive and neural activational differences that cannot be accounted for by the age of acquisition (Chee et al., 2001;Hamrick, 2015;Hamrick et al., 2018;Perani and Abutalebi, 2005;Stein et al., 2009;Wartenburger et al., 2003). ...
Making sense of speech in a second language relies on multiple abilities. Differences in brain activity related to proficiency in language tasks have often been attributed to processing demands. However, during naturalistic narrative comprehension, listeners at different proficiency levels may form different representations of the same speech. We hypothesized that the synchronization of these representations across people could thus be used to measure second-language proficiency. Using a searchlight shared response model, we found that highly proficient participants showed synchronization in regions similar to those of native speakers, including in the default mode network and in the lateral prefrontal cortex. In contrast, participants with low proficiency showed more synchronization in auditory cortex and word-level semantic processing areas in the temporal lobe. Moderate proficiency showed the greatest neural diversity, suggesting lower consistency in the source of this partial proficiency. Based on these synchronization differences, we were able to reliably classify the proficiency level or predict behavioral performance on an independent English test in held-out participants, suggesting the identified neural systems represented proficiency-sensitive information that was generalizable to other individuals. These findings suggest higher second-language proficiency leads to a more native-like neural processing of naturalistic language, including in systems beyond the cognitive control network or the core language network.
Highlights
Neural synchronization in second-language speech processing reflects proficiency.
High-proficiency individuals neurally resemble native speakers.
Low-proficiency individuals are synchronized in perceptual and word semantics areas.
Proficiency level can be predicted using neural synchronization signatures.
... To speak more than one language is becoming more and more common worldwide. In fact, according to the last statistics of the European Commission, more than 60% of the population aged between 25 and 64 years can speak at least one additional language (L2) next to their mother tongue (L1). 1 Accordingly, the increasing population of individuals controlling two or more languages has attracted wide interest in neurocognitive research focusing on multilingual processing, language control and code-switching (i.e., Abutalebi & Green, 2007;Fabbro, 2001;Mechelli et al., 2004;Perani et al., 1998;Rodriguez-Fornells et al., 2009). The handling of multiple languages is a complex and multifaceted process that is far from being completely understood and involves both linguistic (i.e., Costa et al., 2006;Costa & Caramazza, 1999;Costa & Sebasti an-Gallés, 2014) and cognitive (i.e., Abutalebi & Green, 2007;Diamond, 2010;Lehtonen et al., 2018;Rodriguez-Fornells et al., 2009;Sullivan et al., 2014) functions. ...
With the worldwide increase in people speaking more than one language, a better
understanding of the behavioral and neural mechanisms governing lexical selection,
lexical access in multiple languages, and code-switching has attracted widespread
interest from several disciplines. Previous studies documented higher costs when
processing a non-native (L2) than a native (L1) language or when switching from L2
to L1. However, studies on auditory language reception are still scarce and did not
take into account the degree of switching experience. Accordingly, in the present
study, we combined behavioral and electrophysiological measurements to assess
lexical access in L1 and L2 as well as code-switching in professional simultaneous
interpreters, trainee interpreters, foreign language teachers, and Anglistics students
while the participants performed a bilingual auditory lexical decision task. The purpose
of this study was to expand the knowledge on code-switching in auditory language
processing and examine whether the degree of simultaneous interpretation
experience might reduce switching costs. As a main result, we revealed that L2
compared to L1 trials, as well as switch compared to non-switch trials generally
resulted in lower accuracies, longer reaction times, and increased N400 amplitudes in
all groups of participants. Otherwise, we did not reveal any influence of switching
direction and interpretation expertise on N400 parameters. Taken together, these
results suggest that a late age of L2 acquisition leads to switching costs, irrespective
of proficiency level. Furthermore, we provided first evidence that simultaneous
interpretation training does not diminish switching costs, at least when focusing on
lexical access.
... process and learn language in that language acquisition may occur most easily during earlier years of life. However, individuals may still achieve fluency during adult years 8 (Krashen, 1973, Perani, 1998. Children who acquire a second language before puberty tend to speak the language without an accent, while older learners speak the second language with an accent (Freeman, 2004). ...
The purpose of this study was to determine the effect of bilingual music therapy
on expressive language output in special needs children learning English in early
childhood classrooms. Eleven English language learners participated in either an English�only control group or a Bilingual experimental group. In the English-only group, the
researcher utilized Western songs, and spoke and sang only in English. In the Bilingual
group, the researcher sang traditional Latin American folk songs in Spanish and English,
and communicated with the students bilingually. Pretest and posttest data were analyzed
on the Woodcock-Mufioz Language Survey-Revised (WMLS-R) and the school district's
Pre-Kindergarten Assessment Chart (PKAC) to determine gains in expressive
communication within each group and differences between control and experimental
groups. While improvement was noted on the WMLS-R, t tests showed it was not
statistically significant. PKAC scores were analyzed graphically. Students' PKAC data
revealed improvement in expressive language bilingually, with the Bilingual group
experiencing greater improvement.
... He concluded that there was a more extensive activation pattern for the first language than for the second and that the activation pattern for the second language was similar to that happening for the unknown language. Later on, Perani (1998) duplicated this study with high proficiency early and late bilinguals and concluded that both groups showed similar activation areas while listening to the second language. Thus, it can be concluded that proficiency, rather than age alone, is the determining factor for late bilingualism. ...
This book investigates the role native language plays in the process of acquiring a second language within a bilingual educational model. The research presented is based on a 2-year longitudinal study of students in a bilingual school. Particular attention is paid to the development of academic language proficiency. Performance in both languages was compared between two groups of peers learning in submersion classes in Germany and in Portugal. This comparison allows the assessment of effects of a given bilingual education programme. There is a considerable advantage found for the students who learned in the bilingual environment, both in written and in oral samples. These students developed a more proficient bilingual academic discourse ability; socioeconomic status and cognitive abilities were controlled for. When comparing the results with an external measure for school achievement, the advantage was confirmed. The results also hint at didactic factors which seem to contribute to this performance.
Are an individual’s first (L1) and second (L2) languages represented in shared or distinct brain territories? Using intraoperative electrical stimulation mapping (ESM) in two Basque-Spanish bilinguals with non-growing lesions—thus avoiding confounding effects of adaptive plasticity—this study identified distinct language representations within the left temporal lobe. Stimulation of posterior and anterior superior temporal gyri induced language-selective aphasias, whereas stimulation of the mid-temporal region and inferior fronto-occipital fasciculus produced naming errors without language specificity. These findings highlight both shared and distinct loci for L1 and L2, advancing our understanding of bilingual brain organization.
Supplementary Information
The online version contains supplementary material available at 10.1007/s00701-025-06508-5.
Prior research has established a positive link between bilingualism and creativity. However, despite clear evidence for the positive role of L2 proficiency in creativity, few neuroimaging studies have provided insights into its underlying neural mechanisms. To bridge this gap, we
employed a chain free association task and functional near-infrared spectroscopy (fNIRS) to capture cortical activity in the temporo-parietal junction (TPJ) and the frontopolar cortex (FPC) during the task. Our behavioral results confirmed a positive association between L2 proficiency
and creative performance. Neuroimaging data revealed that TPJ activity in bilinguals positively correlated with their creativity, while FPC activity was negatively correlated with their creativity. Furthermore, mediation analysis indicated that both TPJ and FPC activity mediated the relationship between L2 proficiency and creative performance. These preliminary findings suggest the potential involvement of both the default mode network (DMN) and the executive function
network (EFN) in bilinguals’ creative cognition.
Exercise training has been proposed to counteract age-related cognitive decline through improvements in cardiorespiratory fitness (CRF hypothesis). Research has focused on cognitive domains like attention and processing speed, and one cross-sectional study reported a positive relationship between CRF and language production in older adults. In a randomized controlled trial, we investigated whether these benefits could extend to language comprehension in healthy older adults, and whether bilinguals, for whom language processing is more costly, would exhibit greater benefits than monolinguals. Eighty older English monolinguals and 80 older Norwegian-English bilinguals were randomized into either a 6-month exercise training group or into a passive control group. We assessed CRF (VO2peak) and language comprehension (reaction times to spoken word monitoring) in first (L1, all participants) and second language (L2, bilinguals only), before and after the intervention. We found that monolinguals in the exercise group (compared to the control group) were faster in comprehension following the intervention. Moreover, this effect was mediated by exercise-induced increases in VO2peak, supporting the CRF hypothesis. This extends previous cross-sectional research and establishes a causal link between exercise training and speeded comprehension in older monolinguals. However, despite inducing increased VO2peak, exercise training did not affect bilingual (L1 or L2) comprehension, and bilinguals in both groups were slower after the intervention period. Exploratory analyses suggested that this slowing may be driven by participants with low L2 proficiency, but further research is needed to examine whether bilingual language processing is in fact unaffected by exercise training and its consequent improvements in CRF.
In this contribution in honor of Dr. Judith Kroll, we review behavioral models of bilingualism, bringing the most important examples from the literature to highlight how Judy's work has shaped the field. In the second part of the contribution, we describe the challenges and opportunities of neuroimaging methods applied to bilingualism, and we discuss how recent neuroimaging data have revealed effects of learning and speaking that would have been less easily inferred from behavior alone. In the concluding section, we discuss how recent research in the field incorporates network perspectives to account for social language use variability. We conclude with a section honoring Judy's impact as a researcher and mentor.
Background
Primary progressive aphasia (PPA) is a language-based dementia, causing progressive decline of language functions. Transcranial direct current stimulation (tDCS) can augment effects of speech-and language therapy (SLT). However, this has not been investigated in bilingual patients with PPA.
Objective
We evaluated the case of Mr. G., a French (native language, L1)/Dutch (second language, L2)-speaking 59-year-old male, with logopenic PPA, associated with Alzheimer’s disease pathology. We aimed to characterize his patterns of language decline and evaluate the effects of tDCS applied to the right posterolateral cerebellum on his language abilities and executive control circuits.
Methods
In a within-subject controlled design, Mr. G received 9 sessions of sham and anodal tDCS combined with semantic and phonological SLT in L2. Changes were evaluated with an oral naming task in L2, the Boston Naming Task and subtests of the Bilingual Aphasia Test in in L2 and L1, the Stroop Test and Attention Network Test, before and after each phase of stimulation (sham/tDCS) and at 2-month follow-up.
Results
After anodal tDCS, but not after sham, results improved significantly on oral naming in L2, with generalization to untrained tasks and cross-language transfer (CLT) to L1: picture naming in both languages, syntactic comprehension and repetition in L2, and response times in the incongruent condition of the Attention Network Test, indicating increased inhibitory control.
Conclusions
Our preliminary results are the first to indicate that tDCS applied to the cerebellum may be a valuable tool to enhance the effects of SLT in bilingual patients with logopenic PPA.
Aging is associated with a high prevalence of neural and cognitive changes, which may impair life quality while placing a significant burden on the healthcare system and the economy. Nevertheless, diverse daily activities as well as deliberate practice in several domains have been proposed to benefit brain plasticity and cognition as well as to have the potential to counteract age-related decline through neuroprotective and/or compensatory mechanisms. In this review article, we will provide a summary of the gray matter alterations that have commonly been documented in simultaneous interpreters over the past twenty years. Furthermore, we will review the main literature that examined associations between simultaneous interpreting training and cognitive functions for assessing possible practice-related cognitive benefits in older age. We will also outline future directions for research in this area and highlight interventions aimed at mitigating the effects of aging on neurocognition.
We explored whether and to what extent the neural mechanisms of second language sentence processing resemble those of native speakers by investigating the temporal dynamics of syntactic processing in terms of active or passive voice in reading English sentences by Chinese English Foreign Language (EFL) learners with high or low English proficiency. Participants were divided into two groups based on their proficiency levels in English. Three types of sentences (active, passive and ungrammatical) were presented to participants when their event-related potential responses were recorded at the verbs and the final words. The results showed that high-proficiency participants exhibited a greater anterior negativity at the verb position for ungrammatical sentences compared to active sentences. Furthermore, passive sentences elicited a larger frontal positivity than active sentences at the final word position. Additionally, greater P600 effects were observed for both passive and ungrammatical sentences than active sentences at the final word. The low-proficiency group exhibited a greater anterior negativity at the verb (but not the final word) position. In conclusion, these findings emphasize the role of proficiency as a modulating factor in the processing of English active and passive sentences among Chinese EFL learners. Furthermore, the processing of English active and passive sentences by these learners can be conceptualized as a three-stage process: prediction, correction and integration, representing the underlying cognitive mechanisms. This study provides novel insights into the understanding of the cognitive mechanism involved in second language sentence processing.
Reading is a culturally acquired skill that is foundational to academic and personal growth. Unlike oral language skills, reading must be acquired through education. It is generally regarded that multiple cognitive, perceptual, and linguistic skills contribute to the process of reading, and this process, therefore, draws on multiple neurobiological systems that evolved within the brain for other purposes. A neurobiological level of analysis should provide insights into the reading process that can ultimately inform educational approaches which are most effective for different types of learners acquiring different types of scripts. This focus supplements a cognitive level of analysis, involving processes which cannot be directly observed (like metalinguistic awareness), as well as a level of analysis on observable behaviors, which does not specify learning mechanisms nor sources of learning difficulties (as in dysfluent reading). Focusing on the neurobiological level of analysis, the current chapter aims to provide a state-of-the-art overview of how the human brain adapts to learning to read—over the lifespan, within different types of learners, and across various written languages. We will begin by reviewing how the brain changes during reading development. This account comes from the comparisons between literates vs. illiterates, and children vs. adults. Next, we will examine how reading may differentially influence the brain with respect to the different writing systems and for learning to read in multiple languages. This phenomenon is particularly relevant to a growing population of bilingual learners given the large variabilities in the various scripts. Moving forward, we will consider how developmental dyslexia manifests in monolingual and bilingual readers across different writing systems. Finally, we will summarize how the brain changes in response to intervention for reading difficulties in monolingual readers and discuss the implications for reading intervention for bilingual readers. In this chapter, we hope to synthesize a neurobiological model of reading that can inform the mechanisms of learning and provide insights into effective education.
In real-life communication, individuals use language that carries evident rewarding and punishing elements, such as praise and criticism. A common trend is to seek more praise while avoiding criticism. Furthermore, semantics is crucial for conveying information, but such semantic access to native and foreign languages is subtly distinct. To investigate how rule learning occurs in different languages and to highlight the importance of semantics in this process, we investigated both verbal and non-verbal rule learning in first (L1) and second languages (L2) using a reinforcement learning framework, including a semantic rule and a color rule. Our computational modeling revealed that individuals may be more motivated to learn and adhere to rules in an L1 compared to L2, with greater striatum activation during the outcome phase in the L1. Additionally, results on the learning rates and inverse temperature in the two rule learning tasks showed that individuals tend to be conservative and are reluctant to change their judgments regarding rule learning of semantic information. Moreover, the greater the prediction errors, the greater activation of the right superior temporal gyrus in the semantic-rule learning condition, demonstrating that such learning has differential neural correlates than symbolic rule learning. Overall, the findings provide insight into the neural mechanisms underlying rule learning in different languages, and indicate that rule learning involving verbal semantics is not general symbolic learning that resembles a conditioned stimulus-response, but rather has its own specific characteristics.
This chapter provides a broad overview of the collection and analysis of second language (L2) data related to neurocognitive mechanisms. Neuroimaging, electrophysiological, psychophysiological, and neurostimulation approaches are discussed with a particular focus on the most commonly used methods in the field of second language acquisition (SLA): (functional) magnetic resonance imaging ((f)MRI), electroencephalography (EEG), pupillometry, transcranial direct current stimulation (tDCS), and transcutaneous vagus nerve stimulation (tVNS). The chapter addresses pros and cons, highlights example studies, and outlines crucial design considerations for each approach in terms of data collection, analysis, and applicable research questions. All of these neurocognitive or psychophysiological methodologies and more have been used to varying degrees in the field of SLA.
The field of neuropsychology can contribute to bilingualism research from a multidisciplinary perspective that ranges from psycholinguistics and brain imaging studies. While the psycholinguistic approach provides the outlook on linguistic processes in experimental study of patients with brain damage, neural models define the underlying brain areas of such processes and help to predict language deficits in said patients. Current neural models of bilingualism do not provide accurate predictions of deficits in bilinguals with brain damage since they have not been tested in a systematic way. However, they do offer a roadmap for the underlying cognitive and linguistic processes of bilingual language control and speech production. In this chapter, I propose how a neurolinguistic approach to bilingualism might be implemented in neuropsychology by including: (a) the application of traditional methods of cognitive (neuro)psychology to the field of bilingualism, such as dissociations, (b) the use of psycholinguistic methods, and (c) how neurodegenerative diseases may be a neuropsychological paradigm in which one can study bilingual language processes.
The past decades have seen an explosion of research using electrophysiological or neuroimaging techniques for studying the neurocognitive underpinnings of second language (L2) processing. Although this field has a shorter history than does research on language learning more generally, important insights into the neurocognitive basis of L2 processing have driven it to the center stage of language science. In this target article for Language Learning ’s 75th Jubilee volume, I illustrate the field's impressive achievements by selectively reviewing electrophysiological and neuroimaging research on L2 processing and bilingual brain organization. I also review changing perspectives in the field (including individual difference and experience‐based perspectives, neural network approaches, neuroplasticity, and L2‐learning related neural changes) and identified challenges, promises, and future directions (revisit native‐speaker benchmark, increase linguistic diversity, enhance ecological validity, intensify research on child L2 learners’ brain, adopt lifelong approach to L2 learning) that can lead to a better understanding of the neural underpinnings of L2 learning and processing.
The term “Bilingual Advantage” had come to represent a general executive functioning advantage observed for bilinguals. While findings originally looked promising, two key publications released in 2015 drew attention to serious methodological problems in the research body and presented evidence that implied that the literature was affected by a publication and confirmation bias, which favoured significant findings in support of a bilingual advantage.KeywordsBilingualismExecutive functioningAttentionReplication crisis
What happens in the brain when learning a second language? Can speaking more than one language provide cognitive benefits over a lifetime? What implications does an increase in bilingualism have for society? And what are the factors that can promote and support bilingualism in children and adults? This book – a translated and adapted version of Il Cervello Bilingue (2020) - answers these questions and more, providing the reader with a comprehensive yet concise guide on different topics related to bilingualism. Based on the results of the most recent studies conducted internationally, it discusses recent research findings, explains terminology, and elaborates on the current state of the field, with the aim of providing families and society with suggestions about how to encourage bilingualism. Written in an engaging and accessible style, it takes both academics and readers with no prior knowledge of the field on a journey into the bilingual brain.
Bilingualism is a ubiquitous global phenomenon. Beyond being a language experience, bilingualism also entails a social experience, and it interacts with development and learning, with cognitive and neural consequences across the lifespan. The authors of this volume are world renowned experts across several subdisciplines including linguistics, developmental psychology, and cognitive neuroscience. They bring to light bilingualism’s cognitive, developmental, and neural consequences in children, young adults, and older adults. This book honors Ellen Bialystok, and highlights her profound impact on the field of bilingualism research as a lifelong experience. The chapters are organized into four sections: The first section explores the complexity of the bilingual experience beyond the common characterization of “speaking multiple languages.” The next section showcases Ellen Bialystok’s earlier impact on psychology and education; here the contributors answer the question “how does being bilingual shape children’s development?” The third section explores cognitive and neuroscientific theories describing how language experience modulates cognition, behavior, and brain structures and functions. The final section shifts the focus to the impact of bilingualism on healthy and abnormal aging and asks whether being bilingual can stave off the effects of dementia by conferring a “cognitive reserve.”
Making sense of speech in a second language relies on multiple abilities. Differences in brain activity related to proficiency in language tasks have often been attributed to processing demands. However, during naturalistic narrative comprehension, listeners at different proficiency levels may form different representations of the same speech. We hypothesized that the intersubject synchronization of these representations could be used to measure second-language proficiency. Using a searchlight-shared response model, we found highly proficient participants showed synchronization in regions similar to those of native speakers, including in the default mode network and the lateral prefrontal cortex. In contrast, participants with low proficiency showed more synchronization in auditory cortex and word-level semantic processing areas in the temporal lobe. Moderate proficiency showed the greatest neural diversity, suggesting lower consistency in the source of this partial proficiency. Based on these synchronization differences, we were able to classify the proficiency level or predict behavioral performance on an independent English test in held-out participants, suggesting the identified neural systems represented proficiency-sensitive information that was generalizable to other individuals. These findings suggest higher second-language proficiency leads to more native-like neural processing of naturalistic language, including in systems beyond the cognitive control network or the core language network.
Previous studies have identified bilingualism as a protective factor against dementia. Here we aimed to test whether being bilingual at different life stages impacts cognition and brain structure in older adulthood. We included 746 participants from the DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE). Assessment of bilingualism at 3 life stages (early: 13-30, middle: 30-65 and late: over 65 years old) was determined with the Lifetime of Experiences Questionnaire. Individuals reporting bilingualism (i.e., daily use of L2) in the early life stage outperformed monolinguals on learning & memory, working-memory, executive functions and language. Bilingualism in middle life stage showed a significant advantage on learning & memory, while no effect of bilingualism in old life stage was identified. Brain gray matter volume was not associated with L2 use and did not differ between groups. However, stronger correlations between brain gray matter volume in selected brain regions and cognitive performance were found in bilingual participants in the early and middle life stages. Our results indicate that bilingualism in early life might provide a long-lasting protective effect on cognition and shape the brain to sustain cognitive performance in older adulthood.
The last two decades have seen a significant amount of interest in bilingual language learning and processing. A number of computational models have also been developed to account for bilingualism, with varying degrees of success. In this article, we first briefly introduce the significance of computational approaches to bilingual language learning, along with a discussion of the major contributions of current models, their implications, and their limitations. We show that the current models have contributed to progress in understanding the bilingual mind, but significant gaps exist. We advocate a new research agenda integrating progress across different disciplines, such as computational neuroscience, natural language processing, and first language acquisition, to construct a pluralist computational account that combines high‐level cognitive theories and neurobiological foundations for bilingual language learning. We outline the contributions and promises of this interdisciplinary approach in which we view bilingual language learning as a dynamic, interactive, and developmental process. A one‐page Accessible Summary of this article in non‐technical language is freely available in the Supporting Information online and at https://oasis‐database.org
Background
Language treatment for bilinguals with aphasia has been shown to result in gains in both the treated language and the untreated language (i.e., cross-language generalization). However, cross-language generalization is not consistently found. This inconsistency may be due to several factors, such as the age of acquisition of, and proficiency in, each language. One often-overlooked factor that may influence whether cross-language generalization occurs is the manner in which bilinguals learned their second language (L2): in a formal educational context (explicitly) or naturalistically through exposure to the language (implicitly). Prior research suggests that implicit L2 learning results in greater overlap in the representation of the first language (L1) and L2 in the brain, particularly for grammar, compared to explicit learning. In contrast, lexical processing in L1 and L2 is proposed to rely more on shared brain regions regardless of the manner of L2 acquisition. Greater overlap should provide a greater likelihood of cross-language generalization effects from treatment.
Aims
The goal of this study was to determine how the manner of acquisition of L2 may affect cross-language generalization following treatment in L2 separately targeting the lexicon (object naming) and grammar (sentence construction).
Methods & Procedures
Two Spanish-English bilinguals with aphasia each completed two treatment phases in English of 2-4 weeks each, in succession, with one week between them: semantic feature analysis (SFA) targeting object naming, and Verb Network Strengthening Treatment (VNeST) targeting verb retrieval and sentence construction. Pre- and post-treatment assessments and weekly probes were completed for each phase. Participant P1 learned English explicitly in an educational setting, while participant P2 learned English implicitly.
Outcomes & Results
As predicted, P2 showed cross-language generalization after verb/grammar treatment (VNeST) whereas P1 did not. However, contrary to the prediction that both participants should show cross-language generalization after noun treatment (SFA), only P1 showed cross-language generalization of object naming.
Conclusions
Cross-language generalization was observed for both participants but for different aspects of language. The findings suggest that naturalistic second language learning may lead to stronger links between languages in the grammatical system, whereas formal second language learning may lead to stronger links between languages in the lexical-semantic system. Future research should further explore the effects of manner of acquisition as a predictor of language co-activation and cross-language treatment generalization in bilinguals with aphasia.
Professor Michael H. Long (1945-2021) was one of the most influential scholars in the field of second language acquisition. This volume presents a set of chapters that honour some of his key contributions in language teaching and learning. Following a bibliometric analysis of the impact of his research to the field, the volume spans topics such as task-based language teaching, focus on form, age effects, transfer, feedback, interaction, incidental learning, stabilization, among many others.
L’invecchiamento della popolazione è un dato demografico mondiale che assume carattere rilevante in molti Paesi del cosiddetto “primo mondo”, Il concetto di anzianità oggigiorno non può più basarsi su dati misurabili che stabiliscono quando un individuo, nell’arco della sua vita, entra nella fase della vecchiaia. Si tratta di un concetto molto più ampio e articolato che riguarda dimensioni socio-sanitarie, psico-affettive, cognitive e culturali. È necessario dunque ripensare il ruolo attivo della popolazione anziana in una società complessa e plurilingue. Nell’ottica dell’invecchiamento di successo (succesful ageing) e in base al principio di cittadinanza attiva (active citizenship) l’apprendimento delle lingue diviene un aspetto educativo rilevante sia per la partecipazione attiva nella società, sia per i vantaggi cognitivi specifici che tale tipo di apprendimento comporta. Oggi la ricerca neuropsicologica dimostra come l’apprendimento possa avvenire lungo tutto l’arco della vita e come il nostro cervello sia in grado di attivare importati fenomeni di compensazione in grado di arginare il declino cognitivo. In questo contributo si prenderanno in considerazione alcuni aspetti neuropsicologici che dimostrano come l’apprendimento linguistico nell’anziano non solo sia possibile, ma sia auspicabile. Su questi presupposti è importante che la linguistica educativa sviluppi un adeguato modello glotto-geragogico.Parole chiave: Glotto-geragogia. Anziani. Linguistica educativa. Plasticità neuronale. Riserva cognitiva. Modello STAC (Scaffolding Theory of Aging and Cognition). RESUMO: O envelhecimento da população é um dado demográfico global que assume um caráter relevante em muitos países do chamado "primeiro mundo". Hoje o conceito de antiguidade não pode mais ser baseado em dados mensuráveis que estabelecem quando um indivíduo, durante sua vida, entra na fase da velhice. É um conceito muito mais amplo e articulado que diz respeito às dimensões sócio-saúde, psicoafetiva, cognitiva e cultural. É, pois, necessário repensar o papel ativo da população idosa numa sociedade complexa e multilingue. Com vista a um envelhecimento bem sucedido e com base no princípio da cidadania ativa, a aprendizagem de línguas torna-se um aspecto educativo relevante tanto para a participação ativa na sociedade como para as vantagens cognitivas específicas que tal tipo de aprendizagem acarreta. Hoje, a pesquisa neuropsicológica demonstra como o aprendizado pode ocorrer ao longo da vida e como nosso cérebro é capaz de ativar importantes fenômenos de compensação capazes de conter o declínio cognitivo. Neste artigo, serão levados em consideração alguns aspectos neuropsicológicos que demonstram como a aprendizagem de linguagem em idosos não é apenas possível, mas desejável. Com base nesses pressupostos, é importante que a linguística educacional desenvolva um modelo gloto-hieragógico adequado.Palavras-chave: Gloto-hieragogia. Idosos. Linguística educacional. Plasticidade neuronal. Reserva cognitive. Modelo STAC (Scaffolding Theory of Aging and Cognition). ABSTRACT: Population aging is a world demographic data which assumes a relevant character in many of the countries of the so called “first world”. The concept of aging, nowadays, cannot be anymore based on measurable data that establish when a human being, throughout his life, enters the stage of old age. It deals with a much wider and more complex concept that concerns socio-health, psycho-affective, cognitive and cultural dimensions. It is therefore necessary to rethink the active role of old population in a complicated and multilingual society. With a view to a successful aging and according to the principle of active citizenship, language learning becomes an educational aspect relevant both in order to achieve an active social participation and for the specific cognitive advantages that type of learning provides with. Nowadays, the neuropsychological research shows how learning could happen throughout the entire life and how our brain is capable to activate important cognitive compensation phenomena capable of stemming the cognitive decline. This essay will take into consideration some neuropsychological aspects that demonstrate how language learning in old people is not only possible, but desirable. On these assumptions it is important that educational linguistic develops an adequate foreign language learning geragogic model. Keywords: Foreign language learning geragogic model. Old age. Educational linguistics. Neural plasticity. Brain reserve. STAC Model (Scaffolding Theory of Aging and Cognition).
This article firstly introduces an emerging field of bilingual aphasia and discusses the theoretical framework and the significance of bilingual aphasia research. It then provides a review of existing research, focusing on recovery patterns, cross-linguistic transfer effects, and modulating factors in the rehabilitation of bilingual aphasia. It concludes with identification of areas for future research to advance knowledge in bilingual aphasia.
In multilingual people, semantic knowledge is predominantly shared across languages. Providing semantic-focused treatment to people with aphasia has been posited to strengthen connectivity within association cortices that subserve semantic knowledge. In multilingual people, such treatment should result in within- and cross-language generalisation to all languages, although not equally. We investigated treatment effects in two multilingual participants with aphasia who received verb-based semantic treatment in two pre-stroke highly proficient languages. We compared within- and cross-language generalisation patterns across languages, finding within- and cross-language generalisation after treatment in the less-impaired, pre-morbidly more-proficient first-acquired language (L1). This observation supports the theory that connectivity is greater between the lexicon of a pre-morbidly more-proficient L1 and the shared semantic system than the lexicon of a pre-morbidly less-proficient later-acquired language. Our findings of within- and cross-language generalisation patterns could also be explained by both the Competing Mechanisms Theory and the theory of lingering suppression.
Prispevek prikazuje življenjsko delo enega od akterjev tako imenovane kognitivne revolucije, Jacquesa Mehlerja, ki je bil eden uspešnejših evropskih raziskovalcev razvoja človeške kognicije, še posebej razvoja govora. Ob tem članek predstavi glavne predpostavke klasične kognitivne znanosti – modularnost uma ter vlogo narave in vzgoje pri razvoju in delovanju miselnih procesov – in opiše, katere vpoglede v delovanje uma je omogočilo njegovo empirično raziskovanje v preteklih desetletjih. Na kratko tudi predstavi nova spoznanja, ki so kognitivno znanost v zadnjih dveh desetletjih dodobra spremenila in ki so deloma vplivala tudi na njegovo delo. Način, kako je Mehler ta nova spoznanja vedno znova integriral v svoje delo, lahko predstavlja enega od modelov sinteze empiričnega in teoretskega raziskovanja.
In this quantitative meta-analysis, we used the activation likelihood estimation (ALE) approach to address the effects of linguistic distance between first (L1) and second (L2) languages on language-related brain activations. In particular, we investigated how L2-related networks may change in response to linguistic distance from L1. Thus, we examined L2 brain activations in two groups of participants with English as L2 and either (i) a European language (European group, n = 13 studies) or (ii) Chinese (Chinese group, n = 18 studies) as L1. We further explored the modulatory effect of age of appropriation (AoA) and proficiency of L2. We found that, irrespective of L1-L2 distance—and to an extent—irrespective of L2 proficiency, L2 recruits brain areas supporting higher-order cognitive functions (e.g., cognitive control), although with group-specific differences (e.g., the insula region in the European group and the frontal cortex in the Chinese group). The Chinese group also selectively activated the parietal lobe, but this did not occur in the subgroup with high L2 proficiency. These preliminary results highlight the relevance of linguistic distance and call for future research to generalize findings to other language pairs and shed further light on the interaction between linguistic distance, AoA, and proficiency of L2.
PET images of blood flow change that were averaged across individuals were used to identify brain areas related to lexical (single-word) processing, A small number of discrete areas were activated during several task conditions including: modality-specific (auditory or visual) areas activated by passive word input, primary motor and premotor areas during speech output, and yet further areas during tasks making semantic or intentional demands.
Abstract In this study, we compare regional cerebral blood flow (rCBF) while French monolingual subjects listen to continuous speech in an unknown language, to lists of French words, or to meaningful and distorted stories in French. Our results show that, in addition to regions devoted to single-word comprehension, processing of meaningful stories activates the left middle temporal gyrus, the left and right temporal poles, and a superior prefrontal area in the left frontal lobe. Among these regions, only the temporal poles remain activated whenever sentences with acceptable syntax and prosody are presented.
To what extent, if any, does Universal Grammar (UG) constrain second language (L2) acquisition? This is not only an empirical question, but one which is currently investigable. In this context, L2 acquisition is emerging as an important new domain of psycholinguistic research. Three logical possibilities have been articulated regarding the role of UG in L2 acquisition: The first is the “no access” hypothesis that claims that no aspect of UG is available to the L2 learner. The second is the “partial access” hypothesis that claims that only LI instantiated principles and LI instantiated parameter-values of UG are available to the learner. The third, called the “full access” hypothesis, asserts that UG in its entirety constrains L2 acquisition.
In this paper we argue that there is no compelling evidence to support either of the first two hypotheses. Moreover, we provide evidence concerning functional categories in L2 acquisition consistent with the claim that UG is fully available to the L2 learner (see also Flynn 1987; Li 1993; Martohardjono 1992; Schwartz & Sprouse 1991; Thomas 1991; White 1989). In addition, we will attempt to clarify some of currently unclear theoretical issues that arise with respect to positing UG as an explanatory theory of L2 acquisition. We will also investigate in some detail certain crucial methodological questions involved in experimentally testing the role of UG in L2 acquisition and finally, we will present a set of experimental results of our own supporting the “Full Access” hypothesis.
This study examined the production of English consonants by native speakers of Italian. The 240 adult native Italian speakers of English who participated had begun learning English when they emigrated to Canada between the ages of 2 and 23 years. Word-initial, word-medial and word-final tokens of English stops and fricatives were assessed through forced-choice judgments made by native English-speaking listeners, and acoustically. The native Italian subjects' ages of learning (AOL) English exerted a systematic effect on their production of English consonants even though they had lived in Canada for an average of 32 years, and reported speaking English more than Italian. In all but two instances, one or more native Italian subgroup defined on the basis of AOL differed significantly from subjects in a native English (NE) control group. The AOL of the first native Italian subgroup to differ from the NE subjects varied across consonant and syllable position. The results are discussed in terms of hypotheses proposed in the literature concerning the basis of segmental errors in L2 speech production.
Speech segmentation procedures may differ in speakers of different languages. Earlier work based on French speakers listening to French words suggested that the syllable functions as a segmentation unit in speech processing. However, while French has relatively regular and clearly bounded syllables, other languages, such as English, do not. No trace of syllabifying segmentation was found in English listeners listening to English words, French words, or nonsense words. French listeners, however, showed evidence of syllabification even when they were listening to English words. We conclude that alternative segmentation routines are available to the human language processor. In some cases speech segmentation may involve the operation of more than one procedure.
Case Alex, with Sturge-Weber Syndrome affecting the left hemisphere, failed to develop speech throughout early boyhood, and his comprehension of single words and simple commands remained stagnant at an age equivalent of 3-4 years. But then, following left hemidecortication at age 8.5 years and withdrawal of anticonvulsants when he was more than 9 years old, Alex suddenly began to acquire speech and language. He also showed an unusual degree of residual motor capacity on his right side. Alex's remarkable progress in learning speech and language, and the development of his other cognitive abilities, were measured periodically from the age of 9 to 15 years. His most recent scores on tests of receptive and expressive language place him at an age equivalent of 8-10 years. Comparison with the level of function attained in these domains by nine other left hemispherectomized patients with early onset of disease and comparable IQ (range, 40-68) but with early development of speech and language, suggests that, surprisingly, Alex has suffered no permanent disadvantage from his protracted period of mutism and severely limited comprehension. Although the findings in Alex, as in other left- hemispherectomized patients, indicate define limits to the cognitive and linguistic capacity of the isolated right hemisphere, Alex's achievements appear to challenge the widely held view that early childhood is a particularly critical period for acquisition of speech and language or any of their selective aspects, including phonology, grammar, prosody and semantics. It is concluded that clearly articulated, well structured, and appropriate language can be acquired for the first time as late as age 9 years with the right hemisphere alone.
Linguistic experience affects phonetic perception. However, the critical period during which experience affects perception
and the mechanism responsible for these effects are unknown. This study of 6-month-old infants from two countries, the United
States and Sweden, shows that exposure to a specific language in the first half year of life alters infants' phonetic perception.
In order to localize cerebral cognitive or sensorimotor function, activation paradigms are being used in conjunction with PET measures of cerebral activity (e.g., rCBF). The changes in local cerebral activity have two components: a global, region independent change and a local or regional change. As the first step in localizing the regional effects of an activation, global variance must be removed by a normalization procedure. A simple normalization procedure is division of regional values by the whole brain mean. This requires the dependence of local activity on global activity to be one of simple proportionality. This is shown not to be the case. Furthermore, a systematic deviation from a proportional relationship across brain regions is demonstrated. Consequently, any normalization must be approached on a pixel-by-pixel basis by measuring the change in local activity and change in global activity. The changes associated with an activation can be partitioned into global and local effects according to two models: one assumes that the increase in local activity depends on global values and the other assumes independence. It is shown that the increase in activity due to a cognitive activation is independent of global activity. This independence of the (activation) condition effect and the confounding linear effect of global activity on observed local activity meet the requirements for an analysis of covariance, with the "nuisance" variable as global activity and the activation condition as the categorical independent variable. These conclusions are based on analysis of data from 24 scans: six conditions over four normal subjects using a verbal fluency paradigm.(ABSTRACT TRUNCATED AT 250 WORDS)
Speech, in any language, is continuous; speakers provide few reliable cues to the boundaries of words, phrases, or ther meaningful units. To understand speech, listeners must divide the continuous speech stream into portions that correspond to such units. This segmentation process is so basic to human language comprehension that psycholinguists long assumed that all speakers would do it in the same way. In previous research, however, we reported that segmentation routines can be language-specific: speakers of English do not. French has relatively clear syllable boundaries and syllable-based timing patterns, whereas English has relatively unclear syllable boundaries and stress-based timing; thus syllabic segmentation would work more efficiently in the comprehension of French than in the comprehension of English. Our present study suggests that at this level of language processing, there are limits to bilingualism: a bilingual speaker has one and only one basic language.
A technique is described that provides information about relative cerebral responses to differing neurobehavioral tasks in normal subjects studied with positron computed tomography and oxygen-15-labeled water. Simulation studies demonstrate that this technique is sensitive to changes in true local CBF within a physiological range and tends to underestimate relative flow changes at high flow values (greater than 30 ml min-1 100 g-1) and to overestimate these changes for flow values of less than 25 ml min-1 100 g-1. Image acquisition times of 60 s following the arrival of oxygen-15-labeled water in the brain were the most accurate for identifying such relative changes between radioisotope administrations and were not limited by statistical noise from total image counts. Studies in normal volunteers indicate that the technique is highly reproducible, demonstrating a coefficient of variation for small (less than 2 cm2) regions of 2.98 between studies in the same state. Visual stimulation studies in normal volunteers demonstrated relative radioisotope concentration changes between control and stimulated states that are in good agreement with similar results obtained using the same stimulation paradigm but with the use of fluorodeoxyglucose to determine cerebral glucose metabolism.
Long-term auditory-verbal memory comprises, at a neuropsychological level, a number of distinct cognitive processes. In the present study we determined the brain systems engaged during encoding (experiment 1) and retrieval (experiment 2) of episodic auditory-verbal material. In the separate experiments, PET measurements of regional cerebral blood flow (rCBF), an index of neural activity, were performed in normal volunteers during either the encoding or the retrieval of paired word associates. In experiment 1, a dual task interference paradigm was used to isolate areas involved in episodic encoding from those which would be concurrently activated by other cognitive processes associated with the presentation of paired associates, notably priming. In experiment 2, we used the cued retrieval of paired associates from episodic or from semantic memory in order to isolate the neural correlates of episodic memories. Encoding of episodic memory was associated with activation of the left prefrontal cortex and the retrosplenial area of the cingulate cortex, while retrieval from episodic memory was associated with activation of the precuneus bilaterally and of the right prefrontal cortex. These results are compatible with the patterns of activation reported in a previous PET memory experiment in which encoding and retrieval were studied concurrently. They also indicate that separate brain systems are engaged during the encoding and retrieval phases of episodic auditory-verbal memory. Retrieval from episodic memory engages a different, but overlapping, system to that engaged by retrieval from semantic memory, a finding that lends functional anatomical support to this neuropsychological distinction.
We investigated cerebral activity in six normal volunteers using PET to explore the hypothesis that the right hemisphere has a specific role in the interpretation of figurative aspects of language such as metaphors. We also mapped the anatomical structures involved in sentence comprehension. During regional cerebral blood flow measurement subjects were asked to perform three different linguistic tasks: (i) metaphorical comprehension; (ii) literal comprehension of sentences; and (iii) a lexical-decision task. We found that comprehension of sentences compared with the lexical-decision task, induced extensive activation in several regions of the left hemisphere, including the prefrontal and basal frontal cortex, the middle and inferior temporal gyri and temporal pole, the parietal cortex and the precuneus. Comprehension of metaphors was associated with similar activations in the left hemisphere, but in addition, a number of sites were activated in the right hemisphere: the prefrontal cortex, the middle temporal gyrus, the precuneus and the posterior cingulate. We conclude that the interpretation of language involves widespread distributed systems bilaterally with the right hemisphere having a special role in the appreciation of metaphors.
This study determined whether the long-range outcome of first-language acquisition, when the learning begins after early childhood, is similar to that of second-language acquisition. Subjects were 36 deaf adults who had contrasting histories of spoken and sign language acquisition. Twenty-seven subjects were born deaf and began to acquire American Sign Language (ASL) as a first language at ages ranging from infancy to late childhood. Nine other subjects were born with normal hearing, which they lost in late childhood; they subsequently acquired ASL as a second language (because they had acquired spoken English as a first language in early childhood). ASL sentence processing was measured by recall of long and complex sentences and short-term memory for signed digits. Subjects who acquired ASL as a second language after childhood outperformed those who acquired it as a first language at exactly the same age. In addition, the performance of the subjects who acquired ASL as a first language declined in association with increasing age of acquisition. Effects were most apparent for sentence processing skills related to lexical identification, grammatical acceptability, and memory for sentence meaning. No effects were found for skills related to fine-motor production and pattern segmentation.
Data are reviewed from positron emission tomography studies of encoding and retrieval processes in episodic memory. These data suggest a hemispheric encoding/retrieval asymmetry model of prefrontal involvement in encoding and retrieval of episodic memory. According to this model, the left and right prefrontal lobes are part of an extensive neuronal network that subserves episodic remembering, but the two prefrontal hemispheres play different roles. Left prefrontal cortical regions are differentially more involved in retrieval of information from semantic memory and in simultaneously encoding novel aspects of the retrieved information into episodic memory. Right prefrontal cortical regions, on the other hand, are differentially more involved in episodic memory retrieval.
Patients with global amnesia of different aetiologies (n = 11), and patients with probable Alzheimer's disease of recent onset and mild to moderate severity (n = 18) underwent extensive neuropsychological examination, which included the evaluation of multiple components of memory, and a measurement of regional cerebral glucose metabolism with [18F]fluoro-deoxyglucose ([18F]FDG) and PET. In the neuropsychological tests, both global amnesia and Alzheimer's disease patients had impaired episodic long-term memory, while deficits of short-term, semantic and implicit memory were present only in Alzheimer's disease. When local metabolic rates for glucose were compared with values from age- and education-matched normal controls, a common pattern of bilateral hypometabolism was present in the hippocampus, cingulate and frontal basal cortex of both global amnesia and Alzheimer's disease patients. On the other hand, significant hypometabolism was found in the thalamus in only global amnesia, and in the frontal, parietal and temporal associative cortex in only Alzheimer's disease. The results of a multivariate regression analysis of test scores with metabolic data indicated that different clusters of cerebral areas were associated with each of the main components of memory function. These data are in agreement with 'neural network' models of the neural basis of cognition, according to which complex functions are subserved by multiple interconnected cortical and subcortical structures.
The coming of language occurs at about the same age in every healthy child throughout the world, strongly supporting the concept that genetically determined processes of maturation, rather than environmental influences, underlie capacity for speech and verbal understanding. Dr. Lenneberg points out the implications of this concept for the therapeutic and educational approach to children with hearing or speech deficits.
This volume provides a broad overview of current work in aphasia in individuals who speak more than one language. With contributions from many of the leading researchers in the field, the material included, both experimental work and theoretical overviews, should prove useful to both researchers and clinicians. The book should also appeal to a broader audience, including all who have an interest in the study of language disorders in an increasingly multicultural/multilingual world (e.g. students of speech-language pathology and linguistics). The areas of multilingual aphasia addressed in this collection include assessment and treatment, language phenomena (e.g. code-switching), particular language pairs (including a bidialectal study), and the role of cultural context. © 2012 Martin R. Gitterman, Mira Goral, Loraine K. Obler and the authors of individual chapters. All rights reserved.
Change-distribution analysis and intersubject averaging of subtracted positron emission tomography (PET) images are new techniques for detecting, localizing, and quantifying state-dependent focal transients in neuronal activity. We previously described their application to cerebral blood flow images (intravenous bolus H215O, Kety autoradiographic model). We now describe their application to images of H215O regional tissue activity without conversion to units of blood flow. The sensitivity and specificity of response detection and the accuracy of response localization were virtually identical for the two types of images. Response magnitude expressed in percent change from rest was slightly, but consistently smaller in tissue-activity images. Response magnitude expressed in z-score was the same for the two-image types. Most research and clinical applications of functional brain mapping can employ images of H215O tissue activity (intravenous bolus, 40-sec nondynamic scan) without conversion to units of blood flow. This eliminates arterial blood sampling, thereby simplifying and minimizing the invasivity of the PET procedure.
This paper concerns the spatial and intensity transformations that map one image onto another. We present a general technique that facilitates nonlinear spatial (stereotactic) normalization and image realignment. This technique minimizes the sum of squares between two images following nonlinear spatial deformations and transformations of the voxel (intensity) values. The spatial and intensity transformations are obtained simultaneously, and explicitly, using a least squares solution and a series of linearising devices. The approach is completely noninteractive (automatic), nonlinear, and noniterative. It can be applied in any number of dimensions.
Various applications are considered, including the realignment of functional magnetic resonance imaging (MRI) time-series, the linear (affine) and nonlinear spatial normalization of positron emission tomography (PET) and structural MRI images, the coregistration of PET to structural MRI, and, implicitly, the conjoining of PET and MRI to obtain high resolution functional images.
This chapter discusses the kinds of work being pursued within the general principles-and-parameters model as well as some of the thinking that underlies and guides it. The theory of principles and parameters is a particular approach to classical problems of the study of language, guided by certain leading ideas that had been taking shape since the origins of modern generative grammar some forty years ago. The study of generative grammar has been guided by several fundamental problems, each with a traditional flavor. This chapter considers the two states of the language faculty, grammar and Universal Grammar (UG), the distinction between linguistic competence and linguistic performance, and the notion of “infinite use” in relation to competence and performance. It also describes structural descriptions (SDs), an infinite range of symbolic objects specified by a language, the conditions of descriptive adequacy and explanatory adequacy, and the levels of Phonetic Form, Logical Form, and D-Structure. Finally, it examines some properties of the lexicon, with particular emphasis on derivations and representations.
Changes in several postnatal maturational processes during neural development have been implicated as potential mechanisms underlying critical period phenomena. Lenneberg hypothesized that maturational processes similar to those that govern sensory and motor development may also constrain capabilities for normal language acquisition. Our goal, using a bilingual model, was to investigate the hypothesis that maturational constraints may have different effects upon the development of the functional specializations of distinct sub within language. Subjects were 61 adult Chinese/English bilinguals who were exposed to English at different points in development: 13, 46, 710, 1113, and after 16 years of age. Event-related brain potentials (ERPs) and behavioral responses were obtained as subjects read sentences that included semantic anomalies, three types of syntactic violations (phrase structure, specificity constraint, and subjacency constraint), and their controls. The accuracy in judging the grammaticality for the different types of syntactic rules and their associated ERPs was affected by delays in second language exposure as short as 13 years. By comparison the N400 response and the judgment accuracies in detecting semantic anomalies were altered only in subjects who were exposed to English after 1113 and 16 years of age, respectively. Further, the type of changes occurring in ERPs with delays in exposure were qualitatively different for semantic and syntactic processing. All groups displayed a significant N400 effect in response to semantic anomalies, however, the peak latencies of the N400 elicited in bilinguals who were exposed to English between 1113 and >16 years occurred later, suggesting a slight slowing in processing. For syntactic processing. the ERP differences associated with delays in exposure to English were observed in the morphology and distribution of components. Our findings are consistent with the view that maturational changes significantly constrain the development of the neural systems that are relevant for language and, further, that subsystems specialized for processing different aspects of language display different sensitive periods.
FUNCTIONAL magnetic resonance imaging was used to assess inter-subject variability in the cortical representation of language comprehension processes. Moderately fluent French-English bilinguals were scanned while they listened to stories in their first language (L1 = French) or in a second language (L2 = English) acquired at school after the age of seven. In all subjects, listening to L1 always activated a similar set of areas in the left temporal lobe, clustered along the left superior temporal sulcus. Listening to L2, however, activated a highly variable network of left and right temporal and frontal areas, sometimes restricted only to right-hemispheric regions. These results support the hypothesis that first language acquisition relies on a dedicated left-hemispheric cerebral network, while late second language acquisition is not necessarily associated with a reproducible biological substrate. The postulated contribution of the right hemisphere to L2 comprehension1 is found to hold only on average, individual subjects varying from complete right lateralization to standard left lateralization for L2.
WE used positron emission tomography to study brain activity in adults while they were listening to stories in their native language, in a second language acquired after the age of seven, and in a third unknown language. Several areas, similar to those previously observed in monolinguals, were activated by the native but not by the second language. Both the second and the unknown language yielded distinct left-hemispheric activations in areas specialized for phonological processing, which were not engaged by a backward speech control task. These results indicate that some brain areas are shaped by early exposure to the maternal language, and are not necessarily activated by the processing of a second language to which they have been exposed for a limited time later in life.
(C) Lippincott-Raven Publishers.
A model for the organization of language in the adult humans brain is derived from electrical stimulation mapping of several language-related functions: naming, reading, short-term verbal memory, mimicry of orofacial movements, and phoneme identification during neurosurgical operations under local anesthesia. A common peri-Sylvian cortex for motor and language functions is identified in the language dominant hemisphere, including sites common to sequencing of movements and identification of phonemes that may represent an anatomic substrate for the “motor theory of speech perception.” This is surrounded by sites related to short-term verbal memory, with sites specialized for such language functions as naming or syntax at the interface between these motor and memory areas. Language functions are discretely and differentially localized in association cortex, including some differential localization of the same function, naming, in multiple languages. There is substantial individual variability in the exact location of sites related to a particular function, a variability which can be partly related to the patient's sex and overall language ability and which may depend on prior brain injury and, perhaps subtly, on prior experience. A common “specific alerting response” mechanism for motor and language functions is identified in the lateral thalamus of the language–dominant hemisphere, a mechanism that may select the cortical areas appropriate for a particular language function.
Statistical parametric maps are spatially extended statistical processes that are used to test hypotheses about regionally specific effects in neuroimaging data. The most established sorts of statistical parametric maps (e.g., Friston et al. [1991]: J Cereb Blood Flow Metab 11:690–699; Worsley et al. [1992]: J Cereb Blood Flow Metab 12:900–918) are based on linear models, for example ANCOVA, correlation coefficients and t tests. In the sense that these examples are all special cases of the general linear model it should be possible to implement them (and many others) within a unified framework. We present here a general approach that accomodates most forms of experimental layout and ensuing analysis (designed experiments with fixed effects for factors, covariates and interaction of factors). This approach brings together two well established bodies of theory (the general linear model and the theory of Gaussian fields) to provide a complete and simple framework for the analysis of imaging data.
The importance of this framework is twofold: (i) Conceptual and mathematical simplicity, in that the same small number of operational equations is used irrespective of the complexity of the experiment or nature of the statistical model and (ii) the generality of the framework provides for great latitude in experimental design and analysis.
Monolingual French speakers employ a syllable-based procedure in speech segmentation; monolingual English speakers use a stress-based segmentation procedure and do not use the syllable-based procedure. In the present study French-English bilinguals participated in segmentation experiments with English and French materials. Their results as a group did not simply mimic the performance of English monolinguals with English language materials and of French monolinguals with French language materials. Instead, the bilinguals formed two groups, defined by forced choice of a dominant language. Only the French-dominant group showed syllabic segmentation and only with French language materials. The English-dominant group showed no syllabic segmentation in either language. However, the English-dominant group showed stress-based segmentation with English language materials; the French-dominant group did not. We argue that rhythmically based segmentation procedures are mutually exclusive, as a consequence of which speech segmentation by bilinguals is, in one respect at least, functionally monolingual.
Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/33104/1/0000490.pdf
Human amnesia is a clinical syndrome exhibiting the failure to recall past events and to learn new information. Its "pure" form, characterized by a selective impairment of long-term memory without any disorder of general intelligence or other cognitive functions, has been associated with lesions localized within Papez's circuit and some connected areas. Thus, amnesia could be due to a functional disconnection between components of this or other neural structures involved in long-term learning and retention. To test this hypothesis, we measured regional cerebral metabolism with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and positron emission tomography (PET) in 11 patients with "pure" amnesia. A significant bilateral reduction in metabolism in a number of interconnected cerebral regions (hippocampal formation, thalamus, cingulate gyrus, and frontal basal cortex) was found in the amnesic patients in comparison with normal controls. The metabolic impairment did not correspond to alterations in structural anatomy as assessed by magnetic resonance imaging (MRI). These results are the first in vivo evidence for the role of a functional network as a basis of human memory.
Six normal volunteers were studied with positron emission tomography to identify the cortical neural networks that participate in the processing of single words. Activity-related changes in regional cerebral blood flow were measured consecutively on 6 occasions in each subject, 2 while the subject was at rest and 4 while single word language tasks were being performed. The data from each subject were standardized for brain shape and size, reconstructed parallel to the intercommissural line, normalized for global flow differences, and then averaged for each activation condition across the 6 subjects. Significant areas of change in rCBF (P less than 0.05, with appropriate Bonferroni corrections) between task and rest conditions were displayed with reference to the coordinates of a standard neuroanatomical atlas. We have demonstrated that categorical judgements on heard pairs of real words activate neural networks along both superior temporal gyri, but with an anatomical distribution no different from that seen when the subjects listened to nonwords: the tasks would appear to be very different in cognitive demands but not in terms of the distribution of activation. However, during a verb generation task that involved thinking of verbs appropriate to heard nouns presented at a slow rate, the only temporal region activated was the left posterior superior temporal association cortex (Wernicke's area). Further analysis showed that whereas activation in other superior temporal regions, both left and right, correlated with rates of word presentation during the 4 tasks, there was no such correlation in Wernicke's area; evidence that this site is responsible for more than early acoustic processing. During verb generation there was also activation of left premotor and prefrontal cortex (including Broca's area and the supplementary motor area). The supplementary motor area is thought to be involved in the motor planning of speech. The subjects did not vocalize during the task, and therefore it would appear that the act of retrieving words from semantic memory activates networks concerned with the production of speech sounds. We conclude that single word comprehension and retrieval activate very different distributed regions of cerebral cortex, with Wernicke's area the only region engaged by both processes and with participation during silent word generation of networks involved in vocalization.
The identification of brain structures and connections involved in memory functions has depended largely on clinico-pathological studies of memory-impaired patients, and more recently on studies of a primate model of human amnesia. But quantitative neurobehavioural data and detailed neuropathological information are rarely available for the same patients. One case has demonstrated that selective bilateral damage to the hippocampus causes a circumscribed memory impairment in the absence of other intellectual deficits. This finding, in conjunction with evidence from humans and monkeys, indicates that the hippocampus together with adjacent and anatomically related structures is essential for the formation of long-term memory, perhaps by virtue of the extensive reciprocal connections between the hippocampal formation and putative memory storage sites in the neocortex. Although cognitive studies of amnesia provide useful information about the functional organization of normal memory, it has not usually been possible to relate memory impairment to anatomy in living patients. We have developed a high-resolution protocol for imaging the human hippocampus with magnetic resonance that permits visualization of the hippocampal formation in substantial cytoarchitectonic detail, revealing abnormalities in patients with severe and selective memory impairment.
Lenneberg (1967) hypothesized that language could be acquired only within a critical period, extending from early infancy until puberty. In its basic form, the critical period hypothesis need only have consequences for first language acquisition. Nevertheless, it is essential to our understanding of the nature of the hypothesized critical period to determine whether or not it extends as well to second language acquisition. If so, it should be the case that young children are better second language learners than adults and should consequently reach higher levels of final proficiency in the second language. This prediction was tested by comparing the English proficiency attained by 46 native Korean or Chinese speakers who had arrived in the United States between the ages of 3 and 39, and who had lived in the United States between 3 and 26 years by the time of testing. These subjects were tested on a wide variety of structures of English grammar, using a grammaticality judgment task. Both correlational and t-test analyses demonstrated a clear and strong advantage for earlier arrivals over the later arrivals. Test performance was linearly related to age of arrival up to puberty; after puberty, performance was low but highly variable and unrelated to age of arrival. This age effect was shown not to be an inadvertent result of differences in amount of experience with English, motivation, self-consciousness, or American identification. The effect also appeared on every grammatical structure tested, although the structures varied markedly in the degree to which they were well mastered by later learners. The results support the conclusion that a critical period for language acquisition extends its effects to second language acquisition.
Previous research has indicated that young infants can discriminate speech sounds across phonetic boundaries regardless of specific relevant experience, and that there is a modification in this ability during ontogeny such that adults often have difficulty discriminating phonetic contrasts which are not used contrastively in their native language. This pattern of findings has often been interpreted as suggesting that humans are endowed with innate auditory sensitivities which enable them to discriminate speech sounds according to universal phonetic boundaries and that there is a decline or loss in this ability after being exposed to a language which contrasts only a subset of those distinctions. The present experiments were designed to determine whether this modification represents a loss of sensorineural response capabilities or whether it shows a shift in attentional focus and/or processing strategies. In experiment 1, adult English-speaking subjects were tested on their ability to discriminate two non-English speech contrasts in a category-change discrimination task after first being predisposed to adopt one of four perceptual sets. In experiments 2, 3, and 4 subjects were tested in an AX (same/different) procedure, and the effects of both limited training and duration of the interstimulus interval were assessed. Results suggest that the previously observed ontogenetic modification in the perception of non-native phonetic contrasts involves a change in processing strategies rather than a sensorineural loss. Adult listeners can discriminate sounds across non-native phonetic categories in some testing conditions, but are not able to use that ability in testing conditions which have demands similar to those required in natural language processing.
The neural representation of the languages of the polyglot speaker has been highly controversial. We used positron emission tomography (PET) to investigate whether production in a second language (L2) involves the same neural substrates as that of a first language (L1) in normal bilingual subjects who learned L2 after the age of 5 years. Comparison of cerebral blood flow (CBF) when repeating words in L2 and repeating words in L1 yielded only a single significant CBF change: an increase in the left putamen. We hypothesize that this region plays a specific role for articulation in L2. The role of the putamen in articulation is supported by foreign accent syndrome (FAS), which can occur after left putaminal damage. The increased articulatory demands imposed by speaking a second language may require complex motor control for speech production in L2.
It is widely held that conscious recall of past experiences involves a specific system--episodic memory. Patients with amnesia have gross impairments of episodic memory while other kinds of memory remain intact, suggesting that a separable brain system underlies episodic memory. We have used positron emission tomography (PET) to identify components of this system in normal volunteers. A dual-task interference paradigm was used to isolate brain areas associated with acquisition, and a cueing paradigm to isolate the areas concerned with retrieval from verbal episodic memory. Acquisition was associated with activity in the left prefrontal cortex and the retrosplenial area, whereas retrieval was associated with activity in right prefrontal cortex and the precuneus. Our results provide clear evidence that episodic memory involves a network of specific prefrontal and posterior structures which can be fractionated into different component processes.
Clinical data from brain-damaged patients implicates the human hippocampal formation in memory function. We tested the hypothesis that long-term memory function is associated with activation of the hippocampal formation in humans by measuring regional cerebral blood flow changes whilst subjects performed memory tasks. Bilateral hippocampal regional cerebral blood flow was significantly correlated with a measure of the engagement of long-term auditory-verbal memory. No such association was observed for the degree of engagement of auditory-verbal subspan memory. These data provide, for the first time, direct in vivo evidence for the involvement of the hippocampal formation in long-term memory in the intact human brain.
Conventional gradient-echo magnetic resonance imaging (MRI) at 4 Tesla was used successfully to study the activity of Broca's area during internal speech word generation in healthy right-handed volunteers. Activity was demonstrated in the internal gray matter surrounding the ascending ramus of the lateral sulcus, deep to the cortical surface representation of Broca's area, in all the subjects. These studies demonstrate the capability of functional MRI to non-invasively map language related cognitive functions. Such functional mapping has value for both the study of basic neuroscience and neurosurgical planning.