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ABSTRACT: Context is important for recovering language information from talker-induced variability in acoustic signals. In tone perception, previous studies reported similar effects of speech and nonspeech contexts in Mandarin, supporting a general perceptual mechanism underlying tone normalization. However, no supportive evidence was obtained in Cantonese, also a tone language. Moreover, no study has compared speech and nonspeech contexts in the multi-talker condition, which is essential for exploring the normalization mechanism of inter-talker variability in speaking F0. The other question is whether a talker's full F0 range and mean F0 equally facilitate normalization. To answer these questions, this study examines the effects of four context conditions (speech/nonspeech × F0 contour/mean F0) in the multi-talker condition in Cantonese. Results show that raising and lowering the F0 of speech contexts change the perception of identical stimuli from mid level tone to low and high level tone, whereas nonspeech contexts only mildly increase the identification preference. It supports the speech-specific mechanism of tone normalization. Moreover, speech context with flattened F0 trajectory, which neutralizes cues of a talker's full F0 range, fails to facilitate normalization in some conditions, implying that a talker's mean F0 is less efficient for minimizing talker-induced lexical ambiguity in tone perception.
The Journal of the Acoustical Society of America 08/2012; 132(2):1088-99. · 1.55 Impact Factor
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ABSTRACT: Previous studies showed that recognizing a phonetic category produced by different talkers relies on both intrinsic (target-internal) and extrinsic (contextual) cues. Extrinsic cues influence perception when intrinsic cues allow more than one phonetic interpretation. A recent study in this laboratory found that the configuration of tone systems (Cantonese and Mandarin) affects the degree of ambiguity of tones associated with intrinsic cues. In Cantonese which has three level tones, an isolated level pitch can be mapped to any of these three categories. Cantonese but not Mandarin listeners were found to confuse tones in a way biased by relative pitch height of different talkers. The present study tested Cantonese listeners on stimuli from four talkers with different pitch ranges (Female High, Female Low, Male High, and Male Low). Syllable /i/ carrying different F0 contours was embedded in a meaningful sentence with cues of a talker's F0 range. This study found enhanced identification accuracy with contextual cues over performance in isolation (92.25% vs. 51.75%), suggesting that extrinsic context facilitates talker normalization. This finding implies that extrinsic cues are especially useful for a language with intrinsically ambiguous phonetic categories. [Research supported by GRF 455911, NSFC 11074267, NSFC 61135003, and a 973 grant 2012CB720700.].
The Journal of the Acoustical Society of America 04/2012; 131(4):3273. · 1.55 Impact Factor
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ABSTRACT: This study investigates the categorical perception (CP) of pitch contours (level and rising) by native listeners of two tone languages, Mandarin and Cantonese, for both speech and nonspeech. Language background was found to modulate participants’ behavioural and electrophysiological responses to stimuli presented in an active oddball paradigm, comprising a standard and two equally spaced deviants (within- and across-category). The stimuli were divided into two sets according to the results of a two-alternative forced-choice identification test: a rising set, using a standard that listeners identified as high rising tone, and a level set, using a standard that listeners identified as high level tone. For the rising set, both groups of listeners exhibited CP in terms of their behavioural response. However, only Cantonese listeners exhibited a significant CP effect in terms of P300 amplitude. For the level set, the behavioural data revealed a shift in category boundary due, in part, to the range–frequency effect. According to the d′ scores, the CP effect elicited from Mandarin listeners was greater for nonspeech stimuli than for speech, suggesting the presence of apsychophysical boundary. There was no such behavioural contrast for Cantonese listeners. However, Cantonese listeners exhibited a significant CP effect in P300 amplitude that was influenced by the range–frequency effect, as well as a possible secondary phonological boundary. P300 amplitude is believed to index the ease of discrimination of speech stimuli by phonological information. We conclude that Cantonese listeners engaged phonological processing in order to discriminate speech stimuli more efficiently than Mandarin listeners. These findings may be due to the different tonal inventories of Mandarin and Cantonese, with Cantonese listeners required to make finer distinctions in perception of pitch height and slope than Mandarin listeners in order to discriminate the denser tone system of Cantonese.
Language and Cognitive Processes 02/2012; 27(2):184-209. · 1.54 Impact Factor
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ABSTRACT: This study investigates the impact of intertalker variations on the process of mapping acoustic variations on tone categories in two different tone languages.
Pitch stimuli manipulated from four voice ranges were presented in isolation through a blocked-talker design. Listeners were instructed to identify the stimuli that they heard as lexical tones in their native language.
Tone identification of Mandarin listeners exhibited relatively stable normalization regardless of the voice, whereas tone identification of Cantonese listeners was unstable and susceptible to the influence of intertalker variations. In the case of Cantonese listeners, intertalker variations had a larger effect on the perception of F0 height dimension than of F0 slope dimension.
The comparison between Cantonese and Mandarin listeners' performances reveals an interaction of intertalker variations and the types of tone contrasts in each language. For Cantonese tones, which depend heavily on F0 height distinctions, intertalker variations result in F0 overlapping and, consequently, ambiguities among them in isolated tone perception. For Mandarin tones, which are distinctive in terms of their F0 contours, the differences in F0 contours alone seem sufficient to elicit reliable tone identification. Intertalker variations therefore have relatively limited effect on Mandarin tone perception.
Journal of Speech Language and Hearing Research 12/2011; 55(2):579-95. · 1.88 Impact Factor
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ABSTRACT: It has been generally accepted that the left hemisphere is more functionally specialized for language than the right hemisphere for right-handed monolinguals. But more and more studies have also demonstrated right hemisphere advantage for some language tasks with certain participants. A recent comprehensive survey has shown that hemisphere lateralization of language depends on the bilingual status of the participants, with bilateral hemispheric involvement for both languages of early bilinguals, who acquired both languages by age of 6, left hemisphere dominance for language of monolinguals, and also left hemisphere dominance for both languages of late bilinguals, who acquired the second language after age of 6. We propose a preliminary model which takes into account both composition of stimulus words and bilingual status of participants to resolve the apparent controversies regarding hemisphere lateralization of various reading experiments in the literature with focus on Chinese characters, and to predict lateralization patterns for future experiments in Chinese word reading. The bilingual status includes early bilingual, late bilingual and monolingual. However, we have tested this model only with late Chinese-English bilingual participants by using a Stroop paradigm in this paper, though the aim of our model is to disentangle the controversies in the lateralization effect of Chinese character reading. We show here with stimuli written in Chinese single characters that the Stroop effect was stronger when the stimuli were presented to the right than to the left visual field, implying that the language information and color identification/naming may interact more strongly in the left hemisphere. Therefore, our experimental results indicate left hemisphere dominance for Chinese character processing, providing evidence for one part of our model.
Neuropsychologia 03/2011; 49(7):1981-6. · 3.64 Impact Factor
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INTERSPEECH 2011, 12th Annual Conference of the International Speech Communication Association, Florence, Italy, August 27-31, 2011; 01/2011
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Connect. Sci. 01/2010; 22:69-85.
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ABSTRACT: The effect of language on the categorical perception of color is stronger for stimuli in the right visual field (RVF) than in the left visual field, but the neural correlates of the behavioral RVF advantage are unknown. Here we present brain activation maps revealing how language is differentially engaged in the discrimination of colored stimuli presented in either visual hemifield. In a rapid, event-related functional MRI study, we measured subjects' brain activity while they performed a visual search task. Compared with colors from the same lexical category, discrimination of colors from different linguistic categories provoked stronger and faster responses in the left hemisphere language regions, particularly when the colors were presented in the RVF. In addition, activation of visual areas 2/3, responsible for color perception, was much stronger for RVF stimuli from different linguistic categories than for stimuli from the same linguistic category. Notably, the enhanced activity of visual areas 2/3 coincided with the enhanced activity of the left posterior temporoparietal language region, suggesting that this language region may serve as a top-down control source that modulates the activation of the visual cortex. These findings shed light on the brain mechanisms that underlie the hemifield- dependent effect of language on visual perception.
Proceedings of the National Academy of Sciences 06/2009; 106(20):8140-5. · 9.68 Impact Factor
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Proceedings of the IEEE Congress on Evolutionary Computation, CEC 2009, Trondheim, Norway, 18-21 May, 2009; 01/2009
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Journal of Quantitative Linguistics. 01/2008; 15:243-255.
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Proceedings of the IEEE Congress on Evolutionary Computation, CEC 2008, June 1-6, 2008, Hong Kong, China; 01/2008
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Proceedings of the IEEE Congress on Evolutionary Computation, CEC 2007, 25-28 September 2007, Singapore; 01/2007
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Proceedings of the International Joint Conference on Neural Networks, IJCNN 2006, part of the IEEE World Congress on Computational Intelligence, WCCI 2006, Vancouver, BC, Canada, 16-21 July 2006; 01/2006
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ABSTRACT: It has been observed that borrowing within a group of genetically related languages often causes the lexical similarities among them to be skewed. Consequently, it has been proposed that borrowing can sometimes be inferred from such skewing. However, heterogeneity in the rate of lexical replacement, as well as borrowing from other languages, can also give rise to skewed lexical similarities. It is important, therefore, to determine to what degree skewing is a statistically significant indicator of borrowing. Here, we describe a statistical hypothesis test for detecting language contact based on skewing of linguistic characters of arbitrary type. Significant probabilities of correct detection of contact are maintained for various contact scenarios, with low false alarm probability. Our experiments show that the test is fairly robust to substantial heterogeneity in the retention rate, both across characters and across lineages, suggesting that the method can provide an objective criterion against which claims of significant skewing due to contact can be tested, pointing the way for more detailed analysis.
Transactions of the Philological Society 07/2005; 103(2):121 - 146.
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ABSTRACT: Research into the emergence and evolution of human language has received unprecedented attention during the past 15 years. Efforts to better understand the processes of language emergence and evolution have proceeded in two main directions: from the top-down (linguists) and from the bottom-up (cognitive scientists). Language can be viewed as an invading process that has had profound impact on the human phenotype at all levels, from the structure of the brain to modes of cultural interaction. In our view, the most effective way to form a connection between the two efforts (essential if theories for language evolution are to reflect the constraints imposed on language by the brain) lies in computational modelling, an approach that enables numerous hypotheses to be explored and tested against objective criteria and which suggest productive paths for empirical researchers to then follow. Here, with the aim of promoting the cross-fertilization of ideas across disciplines, we review some of the recent research that has made use of computational methods in three principal areas of research into language evolution: language emergence, language change, and language death.
Trends in Ecology & Evolution 06/2005; 20(5):263-9. · 15.75 Impact Factor
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Complexity. 01/2005; 10:50-62.
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Proceedings of the IEEE Congress on Evolutionary Computation, CEC 2005, 2-4 September 2005, Edinburgh, UK; 01/2005
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ABSTRACT: The Kusunda people of central Nepal have long been regarded as a relic tribe of South Asia. They are, or were until recently, seminomadic hunter-gatherers, living in jungles and forests, with a language that shows no similarities to surrounding languages. They are often described as shorter and darker than neighboring tribes. Our research indicates that the Kusunda language is a member of the Indo-Pacific family. This is a surprising finding inasmuch as the Indo-Pacific family is located on New Guinea and surrounding islands. The possibility that Kusunda is a remnant of the migration that led to the initial peopling of New Guinea and Australia warrants additional investigation from both a linguistic and genetic perspective.
Proceedings of the National Academy of Sciences 05/2004; 101(15):5692-5. · 9.68 Impact Factor
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ABSTRACT: This paper presents an innovative method for prosody modeling in Chinese speech recognition. Our method first evaluated the reliability of the prosodic information by which the recognition system dynamically tunes the balance between the spectral scores and prosodic scores. The basic idea of this method is to use prosodic knowledge based on its reliability. The higher the reliability, the more the prosodic information contributes to recognition. Thus, this method will not introduce extra errors but will incorporate more knowledge into the recognition system. Experimental results showed that this method reduced the relative word error rate by as much as 52.9% and 46.0% for Mandarin and Cantonese digit string recognition tasks, respectively. When incorporating tone information into Cantonese Large Vocabulary Continuous Speech Recognition (LVCSR) via the proposed method, a 20.16% relative character error rate reduction was obtained.
International Journal of Speech Technology 01/2004; 7(2):129-140.
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INTERSPEECH 2004 - ICSLP, 8th International Conference on Spoken Language Processing, Jeju Island, Korea, October 4-8, 2004; 01/2004
