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Benefits of free language choice in bilingual individuals with aphasia
Aphasiology
... They suggested that the higher frequency of switching is the result of a strategy to compensate for lexical access difficulties in one language. Similarly, two studies that conducted language switching experiments observed results largely consistent with the idea that difficulties in lexical access may underlie language switching in bilingual individuals with aphasia (Hameau et al., 2022;Mooijman et al., 2024). Conversely, Grunden et al. (2020) obtained several results from a switching experiment that could best be explained by deficits in language control. ...
Previous research examining the factors that determine language choice and voluntary switching mainly involved early bilinguals. Here, using picture naming, we investigated language choice and switching in late Dutch–English bilinguals. We found that naming was overall slower in cued than in voluntary switching, but switch costs occurred in both types of switching. The magnitude of switch costs differed depending on the task and language, and was moderated by L2 proficiency. Self-rated rather than objectively assessed proficiency predicted voluntary switching and ease of lexical access was associated with language choice. Between-language and within-language switch costs were not correlated. These results highlight self-rated proficiency as a reliable predictor of voluntary switching, with language modulating switch costs. As in early bilinguals, ease of lexical access was related to word-level language choice of late bilinguals.
This study examined the role of self-reported attentional control in regulating attentional biases related to trait anxiety. Simple detection targets were preceded by cues labeling potential target locations as threatening (likely to result in negative feedback) or safe (likely to result in positive feedback). Trait anxious participants showed an early attentional bias favoring the threatening location 250 ms after the cue and a late bias favoring the safe location 500 ms after the cue. The anxiety-related threat bias was moderated by attentional control at the 500-ms delay: Anxious participants with poor attentional control still showed the threat bias, whereas those with good control were better able to shift from the threatening location. Thus, skilled control of voluntary attention may allow anxious persons to limit the impact of threatening information.
Background
For speakers with mild to moderate expressive aphasia the ultimate goal of aphasia therapy is to improve verbal functional communication, which may be assessed with the Amsterdam-Nijmegen Test for Everyday Language (ANELT; Blomert et al., 1995). The ANELT is based on a qualitative and transcription-less method of analysis: the scoring is based on personal judgement and directly made from the recording of the test. Previous research (Ruiter et al., 2011) has shown that a quantitative measure for the ANELT not only allows verbal effectiveness (i.e., the amount of essential information conveyed) to be measured more sensitively, but also allows derivation of a measure of verbal efficiency (i.e., average amount of essential information produced per time unit). Although the quantitative scoring further improved the construct validity of the ANELT, there is a limitation that hinders its clinical application: the quantitative measure requires orthographic transcription of the spoken responses to the test. That is, the quantitative scoring is transcription-based.
Aims
In order to work towards clinical applicability of the quantitative measure of the ANELT, this study addressed the potential of a transcription-less variant of the quantitative analysis, in which the amount of essential information is directly quantified on the basis of recording, as a valid and reliable procedure for the measurement of verbal effectiveness.
Methods & Procedures
A total of 56 speakers of Dutch participated: 31 neurologically healthy speakers and 25 persons with aphasia. Monologic discourse elicited with 10 scenarios from an adapted version of the ANELT (Ruiter et al., 2016) was analysed with both a transcription-based quantitative method and a transcription-less quantitative one. Resulting data were systematically compared on the following psychometric properties: internal consistency, inter-rater reliability, construct validity, convergent validity, and known-group validity.
Outcomes & Results
Internal consistency and inter-rater reliability were good and comparable between both scoring methods. Only for one scenario did the transcription-based scoring method yield higher agreement among the raters. With respect to validity, both scoring methods seem to yield measures of the same underlying constructs, show a strong and positive correlation, and allow differentiation between persons with and without aphasia.
Conclusions
Although future research is needed to develop norm scores and investigate other psychometric properties, the result from the comparison demonstrated the potential of the transcription-less quantitative method as a valid and reliable method to analyse monologic discourse elicited with the adapted ANELT.
Language switching is often associated with language competition and switching costs. However, the underlying mechanisms might differ depending on context (free versus cued naming) and modality (production or comprehension). In this study, we assessed how response-stimulus intervals (RSI) influence language-switching costs. Longer RSIs might provide more time for interference from the previous trial to decay and result in smaller switching costs. Mandarin–English bilinguals completed two dual-language production tasks (Experiment 1: cued and voluntary picture naming) and one comprehension task (Experiment 2: animacy judgement) with a short RSI and a long RSI condition. While switching costs were present in all tasks, they were only influenced by RSI length in the cued-production task, with smaller switching costs in the long RSI condition. In contrast, RSI did not influence voluntary-production or comprehension costs. This suggests that bilinguals might apply language control differently to switch languages depending on the type of switching and modality.
Background. Different linguistic contexts place varying amounts of cognitive control on lexical retrieval in bilingual speakers, an issue that is complicated in bilingual people with aphasia (BPWA) due to subsequent language and cognitive deficits. Verbal fluency tasks may offer insight into the interaction between executive and language control in healthy bilinguals and BPWA, by examining conditions with varying cognitive control demands.
Aims. The present study examined switching and clustering in verbal fluency tasks in BPWA and healthy bilinguals across single- and dual-language conditions. We also examined the influence of language processing and language proficiency on switching and clustering performance across the dual-language conditions.
Materials and Methods. Thirty-five Spanish-English BPWA and twenty-two Spanish-English healthy bilinguals completed a language use questionnaire, tests of language processing, and two verbal fluency tasks. The semantic category generation task included four conditions, two single-language conditions (No-Switch L1 and No-Switch L2) which required word production in each language separately, one dual-language condition which allowed switching between languages as desired (Self-Switch), and one dual-language condition which required switching between languages after each response (Forced-Switch). The letter fluency task required word production in single-language contexts.
Outcomes and Results. Overall, healthy bilinguals outperformed BPWA across all measures. Results indicate that switching is more sensitive to increased control demands than clustering, with this effect being more pronounced in BPWA, underscoring the interaction between semantic executive processes and language control in this group. Additionally, for BPWA switching performance relies on a combination of language abilities and language experience measures.
Much research has been dedicated to the effects of bilingualism on executive control (EC). For bilinguals with aphasia , the interplay with EC is complex. In this systematic review, we synthesize research on this topic and provide an overview of the current state of the field. First, we examine the evidence for EC deficits in bilingual persons with aphasia (bPWA). We then discuss the domain generality of bilingual language control impairments. Finally, we evaluate the bilingual advantage hypothesis in bPWA. We conclude that (1) EC impairments in bPWA are frequently observed, (2) experimental results on the relationship between linguistic and domain-general control are mixed, (3) bPWA with language control problems in everyday communication have domain-general EC problems, and (4) there are indications for EC advantages in bPWA. We end with directions for experimental work that could provide better insight into the intricate relationship between EC and bilingual aphasia.
The study of bilingualism has a history that extends from deciphering ancient multilingual texts to mapping the structure of the multilingual brain. The language experiences of individual bilinguals are equally diverse and characterized by unique contexts of acquisition and use that can shape not only sociocultural identity but also cognitive and neural function. Perhaps unsurprisingly, this variability in scholarly perspectives and language experiences has given rise to a range of methods for defining bilingualism. The goal of this article is to initiate a conversation about the utility of a more unified approach to how we think about, study, and measure bilingualism. Using concrete case studies, we illustrate the value of enhancing communication and streamlining terminology across researchers with different methodologies within questions, different questions within domains, and different domains within scientific inquiry. We specifically consider the utility and feasibility of a bilingualism quotient (BQ) construct, discuss the idea of a BQ relative to the well-established intelligence quotient, and include recommendations for next steps. We conclude that though the variability in language backgrounds and approaches to defining bilingualism presents significant challenges, concerted efforts to systematize and synthesize research across the field may enable the construction of a valid and generalizable index of multilingual experience.
The purpose of this study was to examine the relationship between language control, semantic control, and nonverbal control in bilingual aphasia. Twelve bilingual adults with aphasia (BPWA) and 20 age-matched bilingual adults (AMBA) completed a language control task, semantic control task, and nonverbal control task, each designed to examine resistance to distractor interference. AMBA and BPWA exhibited significant effects of control on all tasks. To examine efficiency of control, conflict magnitudes for each task and group were analyzed. Findings revealed that AMBA exhibited larger conflict magnitudes on the semantic control task and nonverbal control task compared to the language control task, whereas BPWA exhibited no difference in conflict magnitudes between the language control task and semantic control task. Further analysis revealed that BPWA semantic control conflict magnitude was smaller than AMBA semantic control conflict magnitude. Taken together, these findings suggest that BPWA present with diminished effects of semantic control. In the final analysis, conflict magnitudes across tasks were correlated. For AMBA, semantic control and nonverbal control conflict magnitudes were significantly correlated, suggesting that these two types of control are related. For BPWA, language control and nonverbal control conflict magnitudes were significantly correlated; however, this finding may capture effects of domain general cognitive control as a function of increased cognitive load, rather than domain general cognitive control as a function of language control.
Research in bilingual healthy controls (BHC) has illustrated that detailed characterization of verbal fluency along with separate measures of executive control stand to inform our understanding of the lexical and cognitive underpinnings of the task. Such data are currently lacking in bilinguals with aphasia (BWA). We aimed to compare the characteristics of verbal fluency performance (semantic, letter) in Bengali–English BWA and BHC, in terms of cross-linguistic differences, variation on the parameters of bilingualism, and cognitive underpinnings. BWA showed significant differences on verbal fluency variables where executive control demands were higher (fluency difference score, number of switches, between-cluster pauses); whilst performed similarly on variables where executive control demands were lower (cluster size, within-cluster pauses). Despite clear cross-linguistic advantage in Bengali for BHC, no cross-linguistic differences were noted in BWA. BWA who were most affected in the independent executive control measures also showed greater impairment in letter fluency condition. Correlation analyses revealed a significant relationship for BWA between inhibitory control and number of correct responses, initial retrieval time, and number of switches. This research contributes to the debate of underlying mechanisms of word retrieval deficits in aphasia, and adds to the nascent literature of BWA in South Asian languages.
As studies of bilingual language control (BLC) seek to explore the underpinnings of bilinguals’ abilities to juggle two languages, different types of language switching tasks have been used to uncover switching and mixing effects and thereby reveal what proactive and reactive control mechanisms are involved in language switching. Voluntary language switching tasks, where a bilingual participant can switch freely between their languages while naming, are being utilized more often due to their greater ecological validity compared to cued switching paradigms. Because this type of task had not yet been applied to language switching in bilingual patients, our study sought to explore voluntary switching in bilinguals with aphasia (BWAs) as well as in healthy bilinguals. In Experiment 1, we replicated previously reported results of switch costs and mixing benefits within our own bilingual population of Catalan-Spanish bilinguals. With Experiment 2, we compared both the performances of BWAs as a group and as individuals against control group performance. Results illustrated a complex picture of language control abilities, indicating varying degrees of association and dissociation between factors of BLC. Given the diversity of impairments in BWAs’ language control mechanisms, we highlight the need to examine BLC at the individual level and through the lens of theoretical cognitive control frameworks in order to further parse out how bilinguals regulate their language switching.
How bilinguals control their languages and switch between them may change across the life span. Furthermore, bilingual language control may depend on the demands imposed by the context. Across 2 experiments, we examined how Spanish-Basque children, teenagers, younger, and older adults switch between languages in voluntary and cued picture-naming tasks. In the voluntary task, bilinguals could freely choose a language while the cued task required them to use a prespecified language. In the cued task, youths and older adults showed larger language mixing costs than young adults, suggesting that using 2 languages in response to cues was more effortful. Cued switching costs, especially when the switching sequence was predictable, were also greater for youths and older adults. The voluntary switching task showed limited age effects. Older adults, but not youths, showed larger switching costs than younger adults. A voluntary mixing benefit was found in all ages, implying that voluntarily using 2 languages was less effortful than using one language across the life span. Thus, while youths and older adults experience greater difficulties using multiple languages in response to external cues, they are affected less when they can freely use their languages. This shows that age effects on bilingual language control are context-dependent.
Purpose
Aphasia is a language disorder caused by acquired brain injury, which generally involves difficulty naming objects. Naming ability is assessed by measuring picture naming, and models of naming performance have mostly focused on accuracy and excluded valuable response time (RT) information. Previous approaches have therefore ignored the issue of processing efficiency, defined here in terms of optimal RT cutoff, that is, the shortest deadline at which individual people with aphasia produce their best possible naming accuracy performance.
The goals of this study were therefore to (a) develop a novel model of aphasia picture naming that could accurately account for RT distributions across response types; (b) use this model to estimate the optimal RT cutoff for individual people with aphasia; and (c) explore the relationships between optimal RT cutoff, accuracy, naming ability, and aphasia severity.
Method
A total of 4,021 naming trials across 10 people with aphasia were scored for accuracy and RT onset. Data were fit using a novel ex-Gaussian multinomial RT model, which was then used to characterize individual optimal RT cutoffs.
Results
Overall, the model fitted the empirical data well and provided reliable individual estimates of optimal RT cutoff in picture naming. Optimal cutoffs ranged between approximately 5 and 10 s, which has important implications for assessment and treatment. There was no direct relationship between aphasia severity, naming RT, and optimal RT cutoff.
Conclusion
The multinomial ex-Gaussian modeling approach appears to be a promising and straightforward way to estimate optimal RT cutoffs in picture naming in aphasia. Limitations and future directions are discussed.
Background: Patients with the semantic variant of Primary Progressive Aphasia (svPPA) offer a unique opportunity to study the relationship between lexical retrieval and semantics, as they are characterised by progressive degradation of central semantic representations. However, there are few studies of how lexical retrieval across languages is affected in multilingual speakers.
Aims: We examine the impact of conceptual degradation in a trilingual patient (TC) with svPPA, to investigate whether the semantic memory breakdown affects her three languages similarly (English-Catalan-Spanish) in different linguistic tasks.
Methods & Procedures: We followed up her performance over one year in several tasks including: (a) naming with or without semantic interference contexts, (b) word translation, (c) word- and sentence-picture matching, (d) associative semantic priming and (e) language switching.
Outcomes & Results: There was significant response consistency between languages in the items that were relatively well-known and more semantically degraded, at least in a standard picture naming task. The patient’s sentence-to-picture matching did not show progressive deterioration in any language. However, some aspects of lexical retrieval showed language-dependency, as indexed by different patterns of performance in semantically-blocked cyclical naming task across languages.
Conclusions: These data suggest that while degradation of central semantic representations affects all languages, this deficit can be amplified or ameliorated by the strength of conceptual to lexical mappings, which varies across languages.
To investigate whether similar control processes are used during single and dual language production, we compared register switching (formal and informal speech in the same language) vs. language switching (French and English). The results across two experiments showed a positive correlation of overall register- and language-switch costs and similar formal French switch costs across the two switching tasks. However, whereas increasing the cue-to-stimulus interval resulted in a reduction of language-switch costs, register-switch costs were unaffected by the interval manipulation. This difference in switch-cost pattern indicates that control processes are not entirely identical during single and dual language production.
Individuals with aphasia frequently show lexical retrieval deficits due to increased interference of semantically related competitors, a phenomenon that can be observed in tasks such as naming pictures grouped by semantic category. These deficits are explained in terms of impaired semantic control, a set of abilities that are to some extent dependent upon executive control (EC). However, the extent to which semantic control abilities can be affected in a second and non-dominant language has not been extensively explored. Additionally, findings in healthy individuals are inconclusive regarding the degree to which semantic processing is shared between languages. In this study, we explored the effect of brain damage on semantic processing by comparing the performance of bilingual individuals with aphasia on tasks involving semantic control during word production and comprehension. Furthermore, we explored whether semantic deficits are related to domain-general EC deficits. First, we investigated the naming performance of Catalan–Spanish bilinguals with fluent aphasia and age-matched healthy controls on a semantically blocked cyclic naming task in each of their two languages (Catalan and Spanish). This task measured semantic interference in terms of the difference in naming latencies between pictures grouped by the same semantic category or different categories. Second, we explored whether lexical deficits extend to comprehension by testing participants in a word-picture matching task during a mixed language condition. Third, we used a conflict monitoring task to explore the presence of EC deficits in patients with aphasia. We found two main results. First, in both language tasks, bilingual patients’ performances were more affected than those of healthy controls when they performed the task in their non-dominant language. Second, there was a significant correlation between the speed of processing on the EC task and the magnitude of the semantic interference effect exclusively in the non-dominant language. Taken together, these results suggest that lexical retrieval may be selectively impaired in bilinguals within those conditions where semantic competition is higher, i.e.,- in their non-dominant language; this could possibly be explained by an excessive amount of inhibition placed upon this language. Moreover, lexico-semantic impairments seem to be at least somewhat related to conflict monitoring deficits, suggesting a certain degree of overlap between EC and semantic control.
Background
Accumulating evidence suggests that the updating, inhibiting and shifting abilities underlying executive control are important for spoken language production in adults. However, little is known about this in children.
Aims
To examine whether children with and without language impairment differ in all or only some of these executive abilities, and whether they show corresponding differences when these abilities are engaged in language production.
Methods & Procedures
Thirty‐three children with specific language impairment (SLI) and 41 typically developing (TD) children (age matched, aged 8–12 years) completed standard executive control tests that measure the updating, inhibiting and shifting abilities. All children were native speakers of Dutch. Moreover, they performed a noun–phrase production task involving picture description within a picture–word interference paradigm. We measured their production accuracy and speed to assess length, distractor and switch effects, which reflect the updating, inhibiting and shifting abilities underlying executive control.
Outcomes & Results
Compared with TD children, the children with SLI had lower scores on all executive control tests. Moreover, they were overall slower and made more errors in the noun–phrase production task. Additionally, the magnitude of the distractor and switch effects was larger for the SLI than for the TD group.
Conclusions & Implications
The results suggest that children with SLI have impaired language production and executive control abilities, and that some of the differences in the executive control abilities between SLI and TD groups were reflected in their language production.
The current study examined the cognitive mechanisms underlying task and language switching by comparing them with each other, and with flanker task performance, at multiple points of the response time distribution. Ninety-eight Spanish-English bilinguals completed cued language and color-shape switching tasks, and 2 versions of a nonlinguistic flanker task. Bilinguals responded more quickly and exhibited smaller mixing costs in the language task, but surprisingly exhibited larger switching costs than in the color-shape task. This language-task disadvantage was especially apparent in slower reaction times (RTs), because switching costs increased significantly through the slowest end of the RT distribution only in the language task (but not in the color-shape task). Although the flanker task resembled the language task to a greater extent than the color-shape task in some measures (e.g., flanker effects were largest in the slowest RT bins, like language switching costs), in other measures the 2 switching tasks resembled each other and the flanker task stood out as different (i.e., trial sequence effects and correlations between tasks in various cost measures). These results reveal that different measures of switching costs even in tasks with very similar designs, vary in the extent to which they measure switching ability, both between tasks, and even between different trials within the same task. Distributional analysis of RTs across tasks suggests that slow responses, particularly when switching between non-naturally competing responses, might not measure switching ability at all, and raises the possibility that smaller switching costs can even reflect reduced ability to juggle tasks in some cases.
We present word prevalence data for 61,858 English words. Word prevalence refers to the number of people who know the word. The measure was obtained on the basis of an online crowdsourcing study involving over 220,000 people. Word prevalence data are useful for gauging the difficulty of words and, as such, for matching stimulus materials in experimental conditions or selecting stimulus materials for vocabulary tests. Word prevalence also predicts word processing times, over and above the effects of word frequency, word length, similarity to other words, and age of acquisition, in line with previous findings in the Dutch language.
Bilingual speakers are suggested to use control processes to avoid linguistic interference from the unintended language. It is debated whether these bilingual language control (BLC) processes are an instantiation of the more domain-general executive control (EC) processes. Previous studies inconsistently report correlations between measures of linguistic and non-linguistic control in bilinguals. In the present study, we investigate the extent to which there is cross-talk between these two domains of control for two switch costs, namely the n-1 shift cost and the n-2 repetition cost. Also, we address an important problem, namely the reliability of the measures used to investigate cross-talk. If the reliability of a measure is low, then these measures are ill-suited to test cross-talk between domains through correlations. We asked participants to perform both a linguistic- and non-linguistic switching task at two sessions about a week apart. The results show a dissociation between the two types of switch costs. Regarding test–retest reliability, we found a stronger reliability for the n-1 shift cost compared to the n-2 repetition cost within both domains as measured by correlations across sessions. This suggests the n-1 shift cost is more suitable to explore cross-talk of BLC and EC. Next, we do find cross-talk for the n-1 shift cost as demonstrated by a significant cross-domain correlation. This suggests that there are at least some shared processes in the linguistic and non-linguistic task.
In this study we examined linguistic and non-linguistic control mechanisms in 20 Spanish–English neurologically healthy bilingual adults and 13 Spanish–English bilingual adults with aphasia. Participants completed two linguistic and two non-linguistic control tasks accounting for low and high complexity. Healthy bilingual results were indicative of domain general cognitive control, whereas patient results were indicative of domain specific cognitive control. The magnitude of conflict required to complete the tasks was also examined. Healthy bilinguals exhibited significant amounts of conflict on all tasks and linguistic and non-linguistic conflict ratios were correlated; whereas patient results revealed significant conflict only on non-linguistic tasks and those conflict ratios were not correlated with linguistic conflict ratios, indicating a dissociation between how patients are controlling information in these two domains. Finally, a relationship between language impairment and language control was identified and brain damage was associated with linguistic and non-linguistic task performance.
Whereas some models claim that language control is part of more general executive control, others have proposed that there is little overlap between these two processes. To shed light on this controversy, we compared switching effects observed in closely matched language switching and task switching tasks. The correlation analyses showed a positive moderate to strong correlation between the two switching variants in all three experiments. The results further showed that language- and task-switch costs differed although the cues, stimuli, response modality, and the number of response alternatives were identical across the two switching variants (Experiments 1), and when additionally the same linguistic tasks (picture naming/category naming) were used in both switching variants (Experiment 3), at least for the error rates. However, similar language- and task-switch costs were obtained when the same non-linguistic tasks (parity/magnitude) were used (Experiment 2). These results point towards overlapping mechanisms for language control and executive control.
Numerous studies in psychology, cognitive neuroscience and psycholinguistics have used pictures of objects as stimulus materials. Currently, authors engaged in cross-linguistic work or wishing to run parallel studies at multiple sites where different languages are spoken must rely on rather small sets of black-and-white or colored line drawings. These sets are increasingly experienced as being too limited. Therefore, we constructed a new set of 750 colored pictures of concrete concepts. This set, MultiPic, constitutes a new valuable tool for cognitive scientists investigating language, visual perception, memory and/or attention in monolingual or multilingual populations. Importantly, the MultiPic databank has been normed in six different European languages (British English, Spanish, French, Dutch, Italian and German). All stimuli and norms are freely available at http://www.bcbl.eu/databases/multipic
Neuroimaging studies suggest that the neural network involved in language control may not be specific to bi-/multilingualism but is part of a domain-general executive control system. We report a trilingual case of a Cantonese (L1), English (L2), and Mandarin (L3) speaker, Dr. T, who sustained a brain injury at the age of 77 causing lesions in the left frontal lobe and in the left temporo-parietal areas resulting in fluent aphasia. Dr. T’s executive functions were impaired according to a modified version of the Stroop color-word test and the Wisconsin Card Sorting Test performance was characterized by frequent perseveration errors. Dr. T demonstrated pathological language switching and mixing across her three languages. Code switching in Cantonese was more prominent in discourse production than confrontation naming. Our case suggests that voluntary control of spoken word production in trilingual speakers shares neural substrata in the frontobasal ganglia system with domain-general executive control mechanisms. One prediction is that lesions to such a system would give rise to both pathological switching and impairments of executive functions in trilingual speakers.
This study examines language control deficits in bilingual aphasia in terms of domain specific cognitive control and domain general cognitive control. Thirty Spanish-English controls and ten Spanish-English adults with aphasia completed the flanker task and a word-pair relatedness judgment task. All participants exhibited congruency effects on the flanker task. On the linguistic task, controls did not show the congruency effect on the first level analysis. However, conflict ratios revealed that the control group exhibited significant effects of language control. Additionally, individual patient analysis revealed overall positive and negative effects of language control impairment and a benefit from semantically related word-pairs. Patient data suggest a dissociation between the mechanisms of language control and cognitive control, thus providing evidence for domain specific cognitive control. The influence of language proficiency on speed of translation was also examined. Generally, controls were faster when translating into their dominant language, whereas the patients did not show the same trends.
We use the results of a large online experiment on word knowledge in Dutch to investigate variables influencing vocabulary size in a large population and to examine the effect of word prevalence -the percentage of a population knowing a word- as a measure of word occurrence. Nearly 300,000 participants were presented with about 70 word stimuli (selected from a list of 53,000 words) in an adapted lexical decision task. We identify age, education and multilingualism as the most important factors influencing vocabulary size. The results suggest that the accumulation of vocabulary throughout life and in multiple languages mirrors the logarithmic growth of number of types with number of tokens observed in text corpora (Herdan's law). Moreover, the vocabulary that multilinguals acquire in related languages seems to increase their L1 vocabulary size and outweighs the loss caused by decreased exposure to L1. In addition, we show that corpus word frequency and prevalence are complementary measures of word occurrence covering a broad range of language experiences. Prevalence is shown to be the strongest independent predictor of word processing times in the Dutch Lexicon Project, making it an important variable for psycholinguistic research.
Background: Lexical access in bilinguals can be influenced by the demands that different interactional contexts pose on cognitive control processes. However, how varying cognitive control demands impact lexical access in bilingual persons with aphasia (BPWA) remains unclear. Verbal fluency tasks may provide valuable insights into the interplay between cognitive control and lexical access in BPWA by addressing word generation abilities in language contexts that exert varying degrees of cognitive control effort.
Aims: The present study aimed to examine the performance of BPWA on a semantic category generation task that required word retrieval in single and dual-language contexts under varying cognitive control demands and a traditional letter fluency task conducted in single-language contexts. We also examined the associations between verbal fluency performance and (i) bilingual language history, and (ii) performance on standardized language assessments in both BPWA and healthy bilinguals.
Methods and Procedures: Thirteen Spanish-English BPWA and twenty-two Spanish-English healthy bilinguals completed a language use questionnaire, verbal fluency testing and standardized language assessments in each language. The semantic category generation task included four conditions: two conditions examined word retrieval in the first-acquired (L1) and second-acquired language (L2) in single language contexts (No Switch-L1 and No Switch-L2) and two conditions elicited word retrieval in dual-language contexts (Self-Switch and Forced-Switch) with low and high cognitive control demands by allowing or restricting switching across languages. The letter fluency task was administered in single language contexts only (F, A, S for English and P, M, R for Spanish). Verbal fluency performance was compared across conditions and groups using multivariate analyses. Further, correlational analyses were used to examine associations between verbal fluency tasks and bilingual language history, language assessments, and cognitive function.
Outcomes and Results: Overall, the healthy bilinguals produced a higher proportion of accurate words in both verbal fluency tasks relative to the BPWA. Results indicate that BPWA were more sensitive to the effects of increased cognitive control on lexical access relative to healthy bilinguals. BPWA and healthy bilinguals’ performance on both verbal fluency tasks was associated with metrics of bilingual language history and standardized language assessments. Additionally, for BPWA, L2 letter fluency performance was associated with cognitive function.
Conclusion: Our findings suggest that verbal fluency tasks can help characterize the impact of cognitive control on lexical access in BPWA in single and mixed language contexts with important clinical implications.
How bilinguals switch between languages depends on the context. In a voluntary context, bilinguals are free to decide when to switch, whereas in a cued context they are instructed when to switch. While using two languages may be more costly than using one in cued switching ('mixing cost'), recent evidence suggests that voluntarily using two languages may be less effortful than using one ('mixing benefit'). Direct comparisons between mandatory and voluntary switching, however, are needed to better understand the effects of the interactional context on bilingual language control. The current study compared mandatory and voluntary switching within the same task, thus keeping the overall task characteristics the same. We observed overall slower mandatory responses and larger mandatory than voluntary mixing and switching effects. Thus, using two languages is more costly in a mandatory than voluntary context, showing that the interactional context can affect the effort needed to control two languages.
Mixing languages within a sentence or a conversation is a common practice among many speakers of multiple languages. Language mixing found in multilingual speakers with aphasia has been suggested to reflect deficits associated with the brain lesion. In this paper, we examine language mixing behaviour in multilingual people with aphasia to test the hypothesis that the use of language mixing reflects a communicative strategy. We analysed connected language production elicited from 11 individuals with aphasia. Words produced were coded as mixed or not. Frequencies of mixing were tabulated for each individual in each of her or his languages in each of two elicitation tasks (Picture sequence description, Narrative production). We tested the predictions that there would be more word mixing: for participants with greater aphasia severity; while speaking in a language of lower post-stroke proficiency; during a task that requires more restricted word retrieval; for people with non-fluent aphasia, while attempting to produce function words (compared to content words); and that there would be little use of a language not known to the interlocutors. The results supported three of the five predictions. We interpret our data to suggest that multilingual speakers with aphasia mix words in connected language production primarily to bypass instances of word-retrieval difficulties, and typically avoid pragmatically inappropriate language mixing.
Background: People with aphasia report preferences for specially formatted health information materials, but there is little evidence that modified materials result in improved comprehension. Potential explanations for this include language included not taking account of aphasic processing difficulties, topics unrelated to aphasia, lack of clarity regarding the use of images, and the lack of end-user involvement in the design. Additionally, no definitive criteria for production of accessible information have been identified.
Aims: The first aim of this study was to collaborate with people with aphasia in an iterative design process to develop and finalise accessible information materials. The second aim was to identify definitive criteria for use in the future production of information materials for people with aphasia.
Methods and procedure: Prototype materials were developed for the study, were based on criteria identified from the existing research into aphasia-accessible information, and on the evidence base concerning language processing in aphasia. Fourteen people with aphasia took part in two rounds of consensus group meetings and viewed information about aphasia presented within the prototype materials. Consensus points were identified within the groups through discussion and through ratings using Likert scales. The set of consensus points and ratings were adapted into criteria for graphic designers to incorporate into subsequent designs of the materials, in order to generate a final version, and related criteria.
Outcomes and results: The group discussions and the ratings of materials led to the identification of an agreed layout within which to present information, and specific criteria for the following: information consisting of one proposition expressed via everyday words and canonical syntactic forms; one or two images relating directly to keywords; sans serif typography with keyword emphasis. Individual preferences with regard to image types were identified. Novel criteria were identified in the study, relating to layout, language, images and typography. These were added to the original set of criteria to form definitive criteria for use in the development of accessible aphasia materials.
Conclusions: This study successfully involved people with aphasia in the design process to produce novel materials, and related design criteria. The resulting materials and criteria differ from those previously proposed, by reflecting directly people with aphasia’s views and preferences, and by incorporating language and images suitable for people with aphasia, based on the existing research evidence and the outcomes of this study. The materials and criteria have the potential to improve people with aphasia’s understanding of health information.
Background: Language mixing in bilingual speakers with aphasia has been reported in a number of research studies, but the reasons for the mixing and whether it reflects typical or atypical behaviour has been a matter of debate.
Aims: In this study, we tested the hypothesis that language mixing behaviour in bilingual aphasia reflects lexical retrieval difficulty.
Methods & procedures: We recruited a Hebrew-English bilingual participant with mild-moderate non-fluent agrammatic aphasia and assessed his languages at three timepoints. We analysed the participant’s Hebrew and English production for retrieval during single-word naming, sentences, and discourse, and identified all instances of language mixing.
Outcomes & Results: We found that there was a greater frequency of language mixing during production of more difficult lexical items, namely the post-morbidly less proficient language (compared to the more proficient language), function words (compared to content words), and single-word naming (compared to retrieval in the context of connected speech tasks), but not for verbs (compared to nouns).
Conclusions: In this bilingual participant with non-fluent aphasia, language mixing behaviour closely resembles lexical retrieval difficulty. Thus, we suggest that bilingual speakers with aphasia may mix their languages as a strategy to maximise communication.
Bilingual language switching has been studied extensively in cued picture naming paradigms, instructing bilinguals when to switch between languages. However, in daily life, bilinguals often switch freely, without external instruction. This study examined when and why bilinguals switch voluntarily. Spanish-Basque bilinguals frequently switched between their languages and their language choice was related to the ease of lexical access. Words that were slow to be accessed in Basque were more often named in Spanish and vice versa. In terms of response times, switching costs were observed not only in the cued but also in the voluntary task. However, while cued switching showed a mixing cost (reflecting the cost associated with using two languages rather than one), a mixing benefit was observed for the voluntary task. This suggests that voluntarily using two languages may be less costly than having to stay in one language.
Since Pillsbury [1908. Attention. London: Swan Sonnenschein & Co], the issue of whether attention operates through inhibition or enhancement has been on the scientific agenda. We examined whether overcoming previous attentional inhibition or enhancement is the source of asymmetrical switch costs in spoken noun-phrase production and colour-word Stroop tasks. In Experiment 1, using bivalent stimuli, we found asymmetrical costs in response times for switching between long and short phrases and between Stroop colour naming and reading. However, in Experiment 2, using bivalent stimuli for the weaker tasks (long phrases, colour naming) and univalent stimuli for the stronger tasks (short phrases, word reading), we obtained an asymmetrical switch cost for phrase production, but a symmetrical cost for Stroop. The switch cost evidence was quantified using Bayesian statistical analyses. Our findings suggest that switching between phrase types involves inhibition, whereas switching between colour naming and reading involves enhancement. Thus, the attentional mechanism depends on the language-production task involved. The results challenge theories of task switching that assume only one attentional mechanism, inhibition or enhancement, rather than both mechanisms.
The current study examines the hypothesis that differential aphasia may be due to a problem with language control rather than with language-specific impairment and how this is related to non-linguistic cognitive control abilities. To this end, we report a case study of an L2 dominant French-English bilingual aphasia patient with larger impairments in French than in English. We assessed cross-language interactions using cognates in three lexical decision (LD) tasks, and non-linguistic cognitive control with a flanker task. We also examined functional connectivity between brain regions crucial for language control and language processing. We observed the preservation of cognate effects in a generalized lexical decision task requiring little language control, which indicates intact functionality (and cross-lingual interactivity) of lexical representations. On the other hand, we found diminished linguistic as well as non-linguistic control abilities, suggesting a domain general control impairment. Resting-state functional Magnetic Resonance Imaging (rs-fMRI) analysis revealed altered connectivity between the patient’s language control and processing network, consistent with the behavioral data. Altogether, these results are in line with the hypothesis that differential aphasia may originate from general cognitive control difficulties.
Background
Until today, there is no satisfying explanation for why one language may recover worse than another in differential bilingual aphasia. One potential explanation that has been largely unexplored is that differential aphasia is the consequence of a loss of language control rather than a loss of linguistic representations. Language control is part of a general control mechanism, managing non-linguistic cognitive control as well. If this system is impaired, patients with differential aphasia could still show bilingual language activation, but they may be unable to manage activation in non-target languages, so that performance in another language is hindered.
Aim
We investigated whether a loss of cognitive control, rather than the loss of word representations in a particular language, might underlie differential aphasia symptoms.
Methods & Procedures
We compared the performance of seven bilinguals with differential and eight bilinguals with parallel aphasia with 19 control bilinguals in a lexical decision and a flanker task to assess bilingual language co-activation and non-linguistic control, respectively.
Outcomes & Results
We found similar cognate effects in the three groups, indicating similar lexical processing across groups. Additionally, we found a larger non-linguistic control congruency effect only for the patients with differential aphasia.
Conclusions & Implications
The present data indicate preserved language co-activation for patients with parallel as well as differential aphasia. Furthermore, our results suggest a general cognitive control dysfunction, specifically for differential aphasia. Taken together, the results of the current study provide further support for the hypothesis of impaired cognitive control abilities in patients with differential aphasia, which has both theoretical and practical implications.
Research has shown that linguistic functions in the bilingual brain are subserved by similar neural circuits as in monolinguals, but with extra-activity associated with cognitive and attentional control. Although a role for the right cerebellum in multilingual language processing has recently been acknowledged, a potential role of the left cerebellum remains largely unexplored.
This paper reports the clinical and fMRI findings in a strongly right-handed (late) multilingual patient who developed differential polyglot aphasia, ataxic dysarthria and a selective decrease in executive function due to an ischemic stroke in the left cerebellum. fMRI revealed that lexical-semantic retrieval in the unaffected L1 was predominantly associated with activations in the left cortical areas (left prefrontal area and left postcentral gyrus), while naming in two affected non-native languages recruited a significantly larger bilateral functional network, including the cerebellum. It is hypothesized that the left cerebellar insult resulted in decreased right prefrontal hemisphere functioning due to a loss of cerebellar impulses through the cerebello-cerebral pathways.
This new edition to the classic book by ggplot2 creator Hadley Wickham highlights compatibility with knitr and RStudio. ggplot2 is a data visualization package for R that helps users create data graphics, including those that are multi-layered, with ease. With ggplot2, it's easy to:
• produce handsome, publication-quality plots with automatic legends created from the plot specification
• superimpose multiple layers (points, lines, maps, tiles, box plots) from different data sources with automatically adjusted common scales
• add customizable smoothers that use powerful modeling capabilities of R, such as loess, linear models, generalized additive models, and robust regression
• save any ggplot2 plot (or part thereof) for later modification or reuse
• create custom themes that capture in-house or journal style requirements and that can easily be applied to multiple plots
• approach a graph from a visual perspective, thinking about how each component of the data is represented on the final plot
This book will be useful to everyone who has struggled with displaying data in an informative and attractive way. Some basic knowledge of R is necessary (e.g., importing data into R). ggplot2 is a mini-language specifically tailored for producing graphics, and you'll learn everything you need in the book. After reading this book you'll be able to produce graphics customized precisely for your problems, and you'll find it easy to get graphics out of your head and on to the screen or page. New to this edition:<
• Brings the book up-to-date with ggplot2 1.0, including major updates to the theme system
• New scales, stats and geoms added throughout
• Additional practice exercises
• A revised introduction that focuses on ggplot() instead of qplot()
• Updated chapters on data and modeling using tidyr, dplyr and broom
As the first chapter in Part II, this chapter turns its attention to education. Focusing on the growing multilingualism in schools, the chapter reviews traditional definitions and types of bilingual education. It frames foreign/second language education, as well as bilingual education, as ways of enacting parallel monolingualisms, and then reviews ways in which this is resisted in classrooms all over the world. It also presents ways in which educators are promoting flexible languaging in teaching, transgressing the strict structures of dual language bilingual classrooms, as well as going beyond the traditional view of separate languages literacies.
We explored the overlap between bilingual language control (bLC) and domain-general executive control (EC) by focusing on inhibitory control processes. We tested 62 bilinguals in linguistic and non-linguistic switching tasks for two types of costs, such as the n-1 shift cost and the n-2 repetition cost. In order to explore the involvement of inhibitory control in bLC and EC, we assessed the pattern of switch costs in the two tasks and then we correlated them between tasks. Results showed reduced n-2 repetition costs as compared to n-1 shift costs in the linguistic task only, suggesting that small amount of inhibition were deployed when switching between languages. Importantly, neither the n-1 shift costs nor the n-2 repetition costs were correlated between tasks. These results, supported by additional evidence from the ex-Gaussian analysis, suggest that inhibitory control is differently involved in bLC and in EC.
Words that have been learned early in life are responded to faster than words that have been acquired later. Subjective ratings of acquisition ages have been successfully employed to study the effect of age of acquisition (AoA). Although a large number of norms exist in many languages, fewer are available for German. Therefore, subjective AoA ratings for 3,259 German words were collected online, including 2,363 nouns and 473 verbs. These words were presented in lists of 140 words, and participants rated the age in years at which they had first learned each word. A split-half correlation testified to a high internal reliability. There were also high correlations with rated AoA values for subsets of the items that had been collected in previous studies, in both German and English. Age and gender were found to influence the ratings very weakly, in that older and male participants tended to give slightly higher age ratings. Education, multilingualism, and frequent usage of languages other than German did not exert an influence on the rating values. These new ratings will extend the currently existing norms available for language and reading research across languages and will provide researchers with a wider choice of word stimuli. The ratings are available expressed in two measurements: age in years, and AoA rated on a 7-point Likert scale.
The present study examined how the updating, inhibiting, and shifting abilities underlying executive control influence spoken noun-phrase production. Previous studies provided evidence that updating and inhibiting, but not shifting, influence picture naming response time (RT). However, little is known about the role of executive control in more complex forms of language production like generating phrases. We assessed noun-phrase production using picture description and a picture-word interference procedure. We measured picture description RT to assess length, distractor, and switch effects, which were assumed to reflect, respectively, the updating, inhibiting, and shifting abilities of adult participants. Moreover, for each participant we obtained scores on executive control tasks that measured verbal and nonverbal updating, nonverbal inhibiting, and nonverbal shifting. We found that both verbal and nonverbal updating scores correlated with the overall mean picture description RTs. Furthermore, the length effect in the RTs correlated with verbal but not nonverbal updating scores, while the distractor effect correlated with inhibiting scores. We did not find a correlation between the switch effect in the mean RTs and the shifting scores. However, the shifting scores correlated with the switch effect in the normal part of the underlying RT distribution. These results suggest that updating, inhibiting, and shifting each influence the speed of phrase production, thereby demonstrating a contribution of all three executive control abilities to language production.
The study investigated the relationship between the efficiency of switching languages and non-linguistic tasks in non-proficient Polish-English bilinguals. The participants performed picture naming that involved switching between L1 and L2 in both directions and a shape or color decision on visually presented figures, which required switching and mixing two different tasks. No relationship between the efficiency in switching languages and non-linguistic tasks was observed. However, increased language switching efficiency was related to high task mixing efficiency, indicating that maintaining two languages and two non-linguistic tasks active is mediated by equivalent control processes. Also, switching from L2 to L1 was more time-consuming than in the opposite direction and participants with the greatest L1 switching disadvantage were the fastest task switchers. These findings suggest that non-proficient bilinguals inhibit their stronger language while switching between L1 and L2 and equivalent inhibitory mechanisms can be responsible for the facilitation of their task switching performance.
The language history questionnaire (LHQ) is an important tool for assessing the linguistic background of bilinguals or second language learners and for generating self-reported proficiency in multiple languages. Previously we developed a generic LHQ based on the most commonly asked questions in published studies (Li, Sepanski & Zhao, 2006). Here we report a new web-based interface (LHQ 2.0) that has more flexibility in functionality, more accuracy in data recording, and more privacy for users and data. LHQ 2.0 achieves flexibility, accuracy, and privacy by using dynamic web-design features for enhanced data collection. It allows investigators to dynamically construct individualized LHQs on the fly and allows participants to complete the LHQ online in multiple languages. Investigators can download and delete the LHQ results and update their user and experiment information on the web. Privacy issues are handled through the online assignment of a unique ID number for each study and password-protected access to data.