Begoña Díaz | Universitat Internacional de Catalunya (original) (raw)

Papers by Begoña Díaz

Frontiers in Psychology, 2022

Previous studies suggest a relationship between second-language learning and voice recognition pr... more Previous studies suggest a relationship between second-language learning and voice recognition processes, but the nature of such relation remains poorly understood. The present study investigates whether phoneme learning relates to voice recognition. A group of bilinguals that varied in their discrimination of a second-language phoneme contrast participated in this study. We assessed participants' voice recognition skills in their native language at the behavioral and brain electrophysiological levels during a voice-avatar learning paradigm. Second-language phoneme discrimination positively correlated with behavioral and brain measures of voice recognition. At the electrophysiological level, correlations were present at two time windows and are interpreted within the dual-process model of recognition memory. The results are relevant to understanding the processes involved in language learning as they show a common variability for second-language phoneme and voice recognition processes.

The Handbook of the Neuroscience of Multilingualism, 2019

Journal of Cognitive Psychology, 2016

Previous studies showed that manipulating the speech production system influenced speech percepti... more Previous studies showed that manipulating the speech production system influenced speech perception. This influence was mediated by task difficulty, listening conditions, and attention. In the present study we investigated the specificity of a somatosensory manipulation-a spoon over the tongue-in passive listening. We measured the Mismatch Negativity (MMN) while participants listened to vowels that differ in their articulation-the tongue height-and familiarity-native and unknown vowels. The same participants heard the vowels in a spoon and no-spoon block. The order of the blocks was counterbalanced across participants. Results showed no effect of the spoon. Instead, starting with the spoon enhanced the MMN amplitude. A second experiment showed the same MMN enhancement for starting with a somatosensory manipulation applied to a non-articulator-the hand. This result suggests that starting a study with a somatosensory manipulation raises attention to the task.

Language, Cognition and Neuroscience, 2017

Current speech perception models disagree over the role of speech production in speech perception... more Current speech perception models disagree over the role of speech production in speech perception. In the current study we aimed to characterize the relationship between speech perception and production by testing a large sample of early and highly proficient Spanish-Catalan bilinguals in a variety of speech perception and production tasks. Speech perception was measured for different phonological processes (sub-lexical and phono-lexical), different language familiarities (native, second, and unknown language), and different sensory modalities (auditory and audiovisual). Speech production ability was assessed in the second language. Non-linguistic auditory and sensory motor abilities were also measured. We used factor analysis to look at the relations between the variables. Results showed a tight relationship between speech perception and production measurements, which was present across phonological processes and language familiarities but was independent of audiovisual and non-linguistic (auditory and sensory-motor) skills.

NeuroImage, 2018

►Recognizing visual speech, compared to face identity, increased LGN responses ►LGN modulation to... more ►Recognizing visual speech, compared to face identity, increased LGN responses ►LGN modulation to speech was higher than for control tasks with non-speech stimuli ►LGN response to speech correlated positively with speechreading accuracy ►LGN modulation to speech was independent of eye-movement and task difficulty 3 The cerebral cortex modulates early sensory processing via feedback connections to sensory pathway nuclei. The functions of this top-down modulation for human behavior are poorly understood. Here, we show that top-down modulation of the visual sensory thalamus (the lateral geniculate body, LGN) is involved in visualspeech recognition. In two independent functional magnetic resonance imaging (fMRI) studies, LGN response increased when participants processed fast-varying features of articulatory movements required for visual-speech recognition, as compared to temporally more stable features required for face identification with the same stimulus material. The LGN response during the visual-speech task correlated positively with the visual-speech recognition scores across participants. In addition, the task-dependent modulation was present for speech movements and did not occur for control conditions involving non-speech biological movements. In face-to-face communication, visual speech recognition is used to enhance or even enable understanding what is said. Speech recognition is commonly explained in frameworks focusing on cerebral cortex areas. Our findings suggest that task-dependent modulation at subcortical sensory stages has an important role for communication: Together with similar findings in the auditory modality the findings imply that task-dependent modulation of the sensory thalami is a general mechanism to optimize speech recognition.

The Journal of Neuroscience, 2019

Developmental dyslexia is characterized by the inability to acquire typical reading and writing s... more Developmental dyslexia is characterized by the inability to acquire typical reading and writing skills. Dyslexia has been frequently linked to cerebral cortex alterations; however recent evidence also points towards sensory thalamus dysfunctions: dyslexics showed reduced responses in the left auditory thalamus (medial geniculate body, MGB) during speech processing in contrast to neurotypical readers. In addition, in the visual modality, dyslexics have reduced structural connectivity between the left visual thalamus (lateral geniculate nucleus, LGN) and V5/MT-a cerebral cortex region involved in visual movement processing. Higher LGN-V5/MT connectivity in dyslexics was associated with the faster rapid naming of letters and numbers (RANln), a measure that is highly correlated with reading proficiency. We here tested two hypotheses that were directly derived from these previous findings. First, we tested the hypothesis that dyslexics have reduced structural connectivity between the left MGB and the auditory motion-sensitive part of the left planum temporale (mPT). Second, we hypothesized that the amount of left mPT-MGB connectivity correlates with dyslexics RANln scores. Using diffusion tensor imaging based probabilistic tracking we show that male adults with developmental dyslexia have reduced structural connectivity between the left MGB and the left mPT-confirming the first hypothesis. Stronger left mPT-MGB connectivity was not associated with faster RANnl scores in dyslexics, but in neurotypical readers. Our findings provide first evidence that reduced cortico-thalamic connectivity in the auditory modality is a feature of developmental dyslexia, and that it may also impact on reading related cognitive abilities in neurotypical readers.

Journal of Neurolinguistics, 2011

Journal of Neurolinguistics, 2012

Brain Structure and Function, 2013

Morphology of the human brain predicts the speed at which individuals learn to distinguish novel ... more Morphology of the human brain predicts the speed at which individuals learn to distinguish novel foreign speech sounds after laboratory training. However, little is known about the neuroanatomical basis of individual differences in speech perception when a second language (L2) has been learned in natural environments for extended periods of time. In the present study, two samples of highly proficient bilinguals were selected according to their ability to distinguish between very similar L2 sounds, either isolated (prelexical) or within words (lexical). Structural MRI was acquired and processed to estimate vertex-wise indices of cortical thickness (CT) and surface area (CSA), and the association between cortical morphology and behavioral performance was inspected. Results revealed that performance in the lexical task was negatively associated with the thickness of the left temporal cortex and angular gyrus, as well as with the surface area of the left precuneus. Our findings, consistently with previous fMRI studies, demonstrate that morphology of the reported areas is relevant for word recognition based on phonological information. Further, we discuss the possibility that increased CT and CSA in sound-to-meaning mapping regions, found for poor non-native speech sounds perceivers, would have plastically arisen after extended periods of increased functional activity during L2 exposure.

Journal of Cognitive Neuroscience, 2006

& Performance-based studies on the psychological nature of linguistic competence can conceal sign... more & Performance-based studies on the psychological nature of linguistic competence can conceal significant differences in the brain processes that underlie native versus nonnative knowledge of language. Here we report results from the brain activity of very proficient early bilinguals making a lexical decision task that illustrates this point. Two groups of Spanish-Catalan early bilinguals (Spanish-dominant and Catalan-dominant) were asked to decide whether a given form was a Catalan word or not. The nonwords were based on real words, with one vowel changed. In the experimental stimuli, the vowel change involved a Catalan-specific contrast that previous research had shown to be difficult for Spanish natives to perceive. In the control stimuli, the vowel switch involved contrasts common to Spanish and Catalan. The results indicated that the groups of bilinguals did not differ in their behavioral and event-related brain potential measurements for the control stimuli; both groups made very few errors and showed a larger N400 component for control nonwords than for control words. However, significant differences were observed for the experimental stimuli across groups: Specifically, Spanish-dominant bilinguals showed great difficulty in rejecting experimental nonwords. Indeed, these participants not only showed very high error rates for these stimuli, but also did not show an error-related negativity effect in their erroneous nonword decisions. However, both groups of bilinguals showed a larger correctrelated negativity when making correct decisions about the experimental nonwords. The results suggest that although some aspects of a second language system may show a remarkable lack of plasticity (like the acquisition of some foreign contrasts), first-language representations seem to be more dynamic in their capacity of adapting and incorporating new information. &

Bilingualism: Language and Cognition, 2015

ABSTRACT People differ in their ability to perceive second language (L2) sounds. In early bilingu... more ABSTRACT People differ in their ability to perceive second language (L2) sounds. In early bilinguals the variability in learning L2 phonemes stems from speech-specific capabilities (Díaz, Baus, Escera, Costa & Sebastián-Gallés, 2008). The present study addresses whether speech-specific capabilities similarly explain variability in late bilinguals. Event-related potentials were recorded (using a design similar to Díaz et al., 2008) in two groups of late Dutch–English bilinguals who were good or poor in overtly discriminating the L2 English vowels /ε-æ/. The mismatch negativity, an index of discrimination sensitivity, was similar between the groups in conditions involving pure tones (of different length, frequency, and presentation order) but was attenuated in poor L2 perceivers for native, unknown, and L2 phonemes. These results suggest that variability in L2 phonemic learning originates from speech-specific capabilities and imply a continuity of L2 phonemic learning mechanisms throughout the lifespan.

PLoS ONE, 2014

Individual differences in second language (L2) phoneme perception (within the normal population) ... more Individual differences in second language (L2) phoneme perception (within the normal population) have been related to speech perception abilities, also observed in the native language, in studies assessing the electrophysiological response mismatch negativity (MMN). Here, we investigate the brain oscillatory dynamics in the theta band, the spectral correlate of the MMN, that underpin success in phoneme learning. Using previous data obtained in an MMN paradigm, the dynamics of cortical oscillations while perceiving native and unknown phonemes and nonlinguistic stimuli were studied in two groups of participants classified as good and poor perceivers (GPs and PPs), according to their L2 phoneme discrimination abilities. The results showed that for GPs, as compared to PPs, processing of a native phoneme change produced a significant increase in theta power. Stimulus time-locked analysis event-related spectral perturbation (ERSP) showed differences for the theta band within the MMN time window (between 70 and 240 ms) for the native deviant phoneme. No other significant difference between the two groups was observed for the other phoneme or nonlinguistic stimuli. The dynamic patterns in the theta-band may reflect early automatic change detection for familiar speech sounds in the brain. The behavioral differences between the two groups may reflect individual variations in activating brain circuits at a perceptual level.

Brain research. Cognitive brain research, 2005

Although the age of acquisition of a language has an effect when learning a second language, the ... more Although the age of acquisition of a language has an effect when learning a second language, the similarity between languages may also have a crucial role. The aim of the present study is to understand the influence of this latter factor in the acquisition of morphosyntactic information. With this purpose, two groups of highly proficient early Catalan-Spanish bilinguals were presented with a repetition-priming paradigm with regular and irregular verbs of Spanish. Catalan and Spanish have a similar suffix (-o) for regular verbs and completely different alternations for irregular verbs. Two types of irregular verbs were studied (semi-regular verbs with a systematic diphthong alternation, sentir-siento, and verbs with idiosyncratic changes, venir-vengo). Regular verbs showed the same centro-parietal N400 priming effect in the second-language speakers (L2) as in primary-language (L1) speakers. However, differences between groups, in the ERP pattern and the topography of the N400 effect,...

Proceedings of the National Academy of Sciences, 2008

Human beings differ in their ability to master the sounds of their second language (L2). Phonetic... more Human beings differ in their ability to master the sounds of their second language (L2). Phonetic training studies have proposed that differences in phonetic learning stem from differences in psychoacoustic abilities rather than speech-specific capabilities. We aimed at finding the origin of individual differences in L2 phonetic acquisition in natural learning contexts. We consider two alternative explanations: a general psychoacoustic origin vs. a speech-specific one. For this purpose, event-related potentials (ERPs) were recorded from two groups of early, proficient Spanish-Catalan bilinguals who differed in their mastery of the Catalan (L2) phonetic contrast /e-/. Brain activity in response to acoustic change detection was recorded in three different conditions involving tones of different length (duration condition), frequency (frequency condition), and presentation order (pattern condition). In addition, neural correlates of speech change detection were also assessed for both native (/o/-/e/) and nonnative (/o/-/ö /) phonetic contrasts (speech condition). Participants' discrimination accuracy, reflected electrically as a mismatch negativity (MMN), was similar between the two groups of participants in the three acoustic conditions. Conversely, the MMN was reduced in poor perceivers (PP) when they were presented with speech sounds. Therefore, our results support a speech-specific origin of individual variability in L2 phonetic mastery. mismatch negativity ͉ event-related potentials ͉ bilingualism L earning a nonnative language sound system is notoriously difficult and often results in the foreign accent that characterizes nonnative speakers. This difficulty in learning a new speech sound system also has consequences for comprehension of the nonnative language. For example, most Japanese native speakers may consider that the English words /rock/ and /lock/ are the same word (1), because the Japanese speech-sound system does not distinguish between the phonemes /r/ and /l/. However, individuals differ significantly in the degree to which they master a nonnative phonetic code, and factors such as the age of acquisition, the amount of exposure, and motivational constraints have a crucial role in final phonetic attainment (2). Despite very early, extended exposure to a L2, many individuals continue to have considerable difficulties in the perception and production of some foreign sounds (3), whereas other nonnative speakers cannot be distinguished from native speakers (4). Discovering the origin of such individual differences is crucial for predicting success in L2 acquisition and for designing learning protocols that maximize the success of L2 learning. To advance in our knowledge of the origin of this individual is the goal of the present study. Specifically, we assess whether such individual differences stem from differences in domain-general psychoacoustic processes or, rather, from differences in specific speech perception abilities.

Learning and Individual Differences, 2012

ABSTRACT The extent to which the phonetic system of a second language is mastered varies across i... more ABSTRACT The extent to which the phonetic system of a second language is mastered varies across individuals. The present study evaluates the pattern of individual differences in late bilinguals across different phonological processes. Fifty-five late Dutch-English bilinguals were tested on their ability to perceive a difficult L2 speech contrast (the English /æ/-/ε/ contrast) in three different tasks: A categorization task, a word identification task and a lexical decision task. As a group, L2 listeners were less accurate than native listeners. However, at the individual level, almost half of the L2 listeners scored within the native range in the categorization task whereas a small percentage scored within the native range in the identification and lexical decision tasks. These results show that L2 listeners' performance crucially depends on the nature of the task, with higher L2 listener accuracy on an acoustic-phonetic analysis task than on tasks involving lexical processes. These findings parallel previous results for early bilinguals, where the pattern of performance was consistent with the processing hierarchy proposed by different models of speech perception. The results indicate that the analysis of patterns of non-native performance can provide important insights concerning the architecture of the speech perception system and the issue of language learnability.

Language Learning, 2012

ABSTRACT In the process of language learning, individuals must acquire different types of linguis... more ABSTRACT In the process of language learning, individuals must acquire different types of linguistic knowledge, such as the sounds of the language (phonemes), how these may be combined to form words (phonotactics), and morphological rules. Early and late bilinguals tend to perform like natives on second language phonological tasks that involve pre-lexical processes (e.g., categorization or identification of isolate phonemes) but their performance decreases when the tasks tap into lexical processes (e.g., accessing to the lexicon storage and selecting the appropiate words). This graded performance across phonological processes is consistent with the processing hierarchy proposed by different models of (native) speech perception. The relation between the first and second languages is further evidenced by the correlation between native and non-native phoneme discrimination of both early and late bilinguals. This correlation provides evidence that individual differences in the command of non-native sounds are caused by a language-specific capability. We propose that the study of second language processes combined with the assessment of individual differences is a relevant field for the understanding of the speech perception architecture.

Journal of Cognitive Neuroscience, 2006

& Performance-based studies on the psychological nature of linguistic competence can conceal sign... more & Performance-based studies on the psychological nature of linguistic competence can conceal significant differences in the brain processes that underlie native versus nonnative knowledge of language. Here we report results from the brain activity of very proficient early bilinguals making a lexical decision task that illustrates this point. Two groups of Spanish-Catalan early bilinguals (Spanish-dominant and Catalan-dominant) were asked to decide whether a given form was a Catalan word or not. The nonwords were based on real words, with one vowel changed. In the experimental stimuli, the vowel change involved a Catalan-specific contrast that previous research had shown to be difficult for Spanish natives to perceive. In the control stimuli, the vowel switch involved contrasts common to Spanish and Catalan. The results indicated that the groups of bilinguals did not differ in their behavioral and event-related brain potential measurements for the control stimuli; both groups made very few errors and showed a larger N400 component for control nonwords than for control words. However, significant differences were observed for the experimental stimuli across groups: Specifically, Spanish-dominant bilinguals showed great difficulty in rejecting experimental nonwords. Indeed, these participants not only showed very high error rates for these stimuli, but also did not show an error-related negativity effect in their erroneous nonword decisions. However, both groups of bilinguals showed a larger correctrelated negativity when making correct decisions about the experimental nonwords. The results suggest that although some aspects of a second language system may show a remarkable lack of plasticity (like the acquisition of some foreign contrasts), first-language representations seem to be more dynamic in their capacity of adapting and incorporating new information. &

Frontiers in Psychology, 2022

Previous studies suggest a relationship between second-language learning and voice recognition pr... more Previous studies suggest a relationship between second-language learning and voice recognition processes, but the nature of such relation remains poorly understood. The present study investigates whether phoneme learning relates to voice recognition. A group of bilinguals that varied in their discrimination of a second-language phoneme contrast participated in this study. We assessed participants' voice recognition skills in their native language at the behavioral and brain electrophysiological levels during a voice-avatar learning paradigm. Second-language phoneme discrimination positively correlated with behavioral and brain measures of voice recognition. At the electrophysiological level, correlations were present at two time windows and are interpreted within the dual-process model of recognition memory. The results are relevant to understanding the processes involved in language learning as they show a common variability for second-language phoneme and voice recognition processes.

The Handbook of the Neuroscience of Multilingualism, 2019

Journal of Cognitive Psychology, 2016

Previous studies showed that manipulating the speech production system influenced speech percepti... more Previous studies showed that manipulating the speech production system influenced speech perception. This influence was mediated by task difficulty, listening conditions, and attention. In the present study we investigated the specificity of a somatosensory manipulation-a spoon over the tongue-in passive listening. We measured the Mismatch Negativity (MMN) while participants listened to vowels that differ in their articulation-the tongue height-and familiarity-native and unknown vowels. The same participants heard the vowels in a spoon and no-spoon block. The order of the blocks was counterbalanced across participants. Results showed no effect of the spoon. Instead, starting with the spoon enhanced the MMN amplitude. A second experiment showed the same MMN enhancement for starting with a somatosensory manipulation applied to a non-articulator-the hand. This result suggests that starting a study with a somatosensory manipulation raises attention to the task.

Language, Cognition and Neuroscience, 2017

Current speech perception models disagree over the role of speech production in speech perception... more Current speech perception models disagree over the role of speech production in speech perception. In the current study we aimed to characterize the relationship between speech perception and production by testing a large sample of early and highly proficient Spanish-Catalan bilinguals in a variety of speech perception and production tasks. Speech perception was measured for different phonological processes (sub-lexical and phono-lexical), different language familiarities (native, second, and unknown language), and different sensory modalities (auditory and audiovisual). Speech production ability was assessed in the second language. Non-linguistic auditory and sensory motor abilities were also measured. We used factor analysis to look at the relations between the variables. Results showed a tight relationship between speech perception and production measurements, which was present across phonological processes and language familiarities but was independent of audiovisual and non-linguistic (auditory and sensory-motor) skills.

NeuroImage, 2018

►Recognizing visual speech, compared to face identity, increased LGN responses ►LGN modulation to... more ►Recognizing visual speech, compared to face identity, increased LGN responses ►LGN modulation to speech was higher than for control tasks with non-speech stimuli ►LGN response to speech correlated positively with speechreading accuracy ►LGN modulation to speech was independent of eye-movement and task difficulty 3 The cerebral cortex modulates early sensory processing via feedback connections to sensory pathway nuclei. The functions of this top-down modulation for human behavior are poorly understood. Here, we show that top-down modulation of the visual sensory thalamus (the lateral geniculate body, LGN) is involved in visualspeech recognition. In two independent functional magnetic resonance imaging (fMRI) studies, LGN response increased when participants processed fast-varying features of articulatory movements required for visual-speech recognition, as compared to temporally more stable features required for face identification with the same stimulus material. The LGN response during the visual-speech task correlated positively with the visual-speech recognition scores across participants. In addition, the task-dependent modulation was present for speech movements and did not occur for control conditions involving non-speech biological movements. In face-to-face communication, visual speech recognition is used to enhance or even enable understanding what is said. Speech recognition is commonly explained in frameworks focusing on cerebral cortex areas. Our findings suggest that task-dependent modulation at subcortical sensory stages has an important role for communication: Together with similar findings in the auditory modality the findings imply that task-dependent modulation of the sensory thalami is a general mechanism to optimize speech recognition.

The Journal of Neuroscience, 2019

Developmental dyslexia is characterized by the inability to acquire typical reading and writing s... more Developmental dyslexia is characterized by the inability to acquire typical reading and writing skills. Dyslexia has been frequently linked to cerebral cortex alterations; however recent evidence also points towards sensory thalamus dysfunctions: dyslexics showed reduced responses in the left auditory thalamus (medial geniculate body, MGB) during speech processing in contrast to neurotypical readers. In addition, in the visual modality, dyslexics have reduced structural connectivity between the left visual thalamus (lateral geniculate nucleus, LGN) and V5/MT-a cerebral cortex region involved in visual movement processing. Higher LGN-V5/MT connectivity in dyslexics was associated with the faster rapid naming of letters and numbers (RANln), a measure that is highly correlated with reading proficiency. We here tested two hypotheses that were directly derived from these previous findings. First, we tested the hypothesis that dyslexics have reduced structural connectivity between the left MGB and the auditory motion-sensitive part of the left planum temporale (mPT). Second, we hypothesized that the amount of left mPT-MGB connectivity correlates with dyslexics RANln scores. Using diffusion tensor imaging based probabilistic tracking we show that male adults with developmental dyslexia have reduced structural connectivity between the left MGB and the left mPT-confirming the first hypothesis. Stronger left mPT-MGB connectivity was not associated with faster RANnl scores in dyslexics, but in neurotypical readers. Our findings provide first evidence that reduced cortico-thalamic connectivity in the auditory modality is a feature of developmental dyslexia, and that it may also impact on reading related cognitive abilities in neurotypical readers.

Journal of Neurolinguistics, 2011

Journal of Neurolinguistics, 2012

Brain Structure and Function, 2013

Morphology of the human brain predicts the speed at which individuals learn to distinguish novel ... more Morphology of the human brain predicts the speed at which individuals learn to distinguish novel foreign speech sounds after laboratory training. However, little is known about the neuroanatomical basis of individual differences in speech perception when a second language (L2) has been learned in natural environments for extended periods of time. In the present study, two samples of highly proficient bilinguals were selected according to their ability to distinguish between very similar L2 sounds, either isolated (prelexical) or within words (lexical). Structural MRI was acquired and processed to estimate vertex-wise indices of cortical thickness (CT) and surface area (CSA), and the association between cortical morphology and behavioral performance was inspected. Results revealed that performance in the lexical task was negatively associated with the thickness of the left temporal cortex and angular gyrus, as well as with the surface area of the left precuneus. Our findings, consistently with previous fMRI studies, demonstrate that morphology of the reported areas is relevant for word recognition based on phonological information. Further, we discuss the possibility that increased CT and CSA in sound-to-meaning mapping regions, found for poor non-native speech sounds perceivers, would have plastically arisen after extended periods of increased functional activity during L2 exposure.

Journal of Cognitive Neuroscience, 2006

& Performance-based studies on the psychological nature of linguistic competence can conceal sign... more & Performance-based studies on the psychological nature of linguistic competence can conceal significant differences in the brain processes that underlie native versus nonnative knowledge of language. Here we report results from the brain activity of very proficient early bilinguals making a lexical decision task that illustrates this point. Two groups of Spanish-Catalan early bilinguals (Spanish-dominant and Catalan-dominant) were asked to decide whether a given form was a Catalan word or not. The nonwords were based on real words, with one vowel changed. In the experimental stimuli, the vowel change involved a Catalan-specific contrast that previous research had shown to be difficult for Spanish natives to perceive. In the control stimuli, the vowel switch involved contrasts common to Spanish and Catalan. The results indicated that the groups of bilinguals did not differ in their behavioral and event-related brain potential measurements for the control stimuli; both groups made very few errors and showed a larger N400 component for control nonwords than for control words. However, significant differences were observed for the experimental stimuli across groups: Specifically, Spanish-dominant bilinguals showed great difficulty in rejecting experimental nonwords. Indeed, these participants not only showed very high error rates for these stimuli, but also did not show an error-related negativity effect in their erroneous nonword decisions. However, both groups of bilinguals showed a larger correctrelated negativity when making correct decisions about the experimental nonwords. The results suggest that although some aspects of a second language system may show a remarkable lack of plasticity (like the acquisition of some foreign contrasts), first-language representations seem to be more dynamic in their capacity of adapting and incorporating new information. &

Bilingualism: Language and Cognition, 2015

ABSTRACT People differ in their ability to perceive second language (L2) sounds. In early bilingu... more ABSTRACT People differ in their ability to perceive second language (L2) sounds. In early bilinguals the variability in learning L2 phonemes stems from speech-specific capabilities (Díaz, Baus, Escera, Costa & Sebastián-Gallés, 2008). The present study addresses whether speech-specific capabilities similarly explain variability in late bilinguals. Event-related potentials were recorded (using a design similar to Díaz et al., 2008) in two groups of late Dutch–English bilinguals who were good or poor in overtly discriminating the L2 English vowels /ε-æ/. The mismatch negativity, an index of discrimination sensitivity, was similar between the groups in conditions involving pure tones (of different length, frequency, and presentation order) but was attenuated in poor L2 perceivers for native, unknown, and L2 phonemes. These results suggest that variability in L2 phonemic learning originates from speech-specific capabilities and imply a continuity of L2 phonemic learning mechanisms throughout the lifespan.

PLoS ONE, 2014

Individual differences in second language (L2) phoneme perception (within the normal population) ... more Individual differences in second language (L2) phoneme perception (within the normal population) have been related to speech perception abilities, also observed in the native language, in studies assessing the electrophysiological response mismatch negativity (MMN). Here, we investigate the brain oscillatory dynamics in the theta band, the spectral correlate of the MMN, that underpin success in phoneme learning. Using previous data obtained in an MMN paradigm, the dynamics of cortical oscillations while perceiving native and unknown phonemes and nonlinguistic stimuli were studied in two groups of participants classified as good and poor perceivers (GPs and PPs), according to their L2 phoneme discrimination abilities. The results showed that for GPs, as compared to PPs, processing of a native phoneme change produced a significant increase in theta power. Stimulus time-locked analysis event-related spectral perturbation (ERSP) showed differences for the theta band within the MMN time window (between 70 and 240 ms) for the native deviant phoneme. No other significant difference between the two groups was observed for the other phoneme or nonlinguistic stimuli. The dynamic patterns in the theta-band may reflect early automatic change detection for familiar speech sounds in the brain. The behavioral differences between the two groups may reflect individual variations in activating brain circuits at a perceptual level.

Brain research. Cognitive brain research, 2005

Although the age of acquisition of a language has an effect when learning a second language, the ... more Although the age of acquisition of a language has an effect when learning a second language, the similarity between languages may also have a crucial role. The aim of the present study is to understand the influence of this latter factor in the acquisition of morphosyntactic information. With this purpose, two groups of highly proficient early Catalan-Spanish bilinguals were presented with a repetition-priming paradigm with regular and irregular verbs of Spanish. Catalan and Spanish have a similar suffix (-o) for regular verbs and completely different alternations for irregular verbs. Two types of irregular verbs were studied (semi-regular verbs with a systematic diphthong alternation, sentir-siento, and verbs with idiosyncratic changes, venir-vengo). Regular verbs showed the same centro-parietal N400 priming effect in the second-language speakers (L2) as in primary-language (L1) speakers. However, differences between groups, in the ERP pattern and the topography of the N400 effect,...

Proceedings of the National Academy of Sciences, 2008

Human beings differ in their ability to master the sounds of their second language (L2). Phonetic... more Human beings differ in their ability to master the sounds of their second language (L2). Phonetic training studies have proposed that differences in phonetic learning stem from differences in psychoacoustic abilities rather than speech-specific capabilities. We aimed at finding the origin of individual differences in L2 phonetic acquisition in natural learning contexts. We consider two alternative explanations: a general psychoacoustic origin vs. a speech-specific one. For this purpose, event-related potentials (ERPs) were recorded from two groups of early, proficient Spanish-Catalan bilinguals who differed in their mastery of the Catalan (L2) phonetic contrast /e-/. Brain activity in response to acoustic change detection was recorded in three different conditions involving tones of different length (duration condition), frequency (frequency condition), and presentation order (pattern condition). In addition, neural correlates of speech change detection were also assessed for both native (/o/-/e/) and nonnative (/o/-/ö /) phonetic contrasts (speech condition). Participants' discrimination accuracy, reflected electrically as a mismatch negativity (MMN), was similar between the two groups of participants in the three acoustic conditions. Conversely, the MMN was reduced in poor perceivers (PP) when they were presented with speech sounds. Therefore, our results support a speech-specific origin of individual variability in L2 phonetic mastery. mismatch negativity ͉ event-related potentials ͉ bilingualism L earning a nonnative language sound system is notoriously difficult and often results in the foreign accent that characterizes nonnative speakers. This difficulty in learning a new speech sound system also has consequences for comprehension of the nonnative language. For example, most Japanese native speakers may consider that the English words /rock/ and /lock/ are the same word (1), because the Japanese speech-sound system does not distinguish between the phonemes /r/ and /l/. However, individuals differ significantly in the degree to which they master a nonnative phonetic code, and factors such as the age of acquisition, the amount of exposure, and motivational constraints have a crucial role in final phonetic attainment (2). Despite very early, extended exposure to a L2, many individuals continue to have considerable difficulties in the perception and production of some foreign sounds (3), whereas other nonnative speakers cannot be distinguished from native speakers (4). Discovering the origin of such individual differences is crucial for predicting success in L2 acquisition and for designing learning protocols that maximize the success of L2 learning. To advance in our knowledge of the origin of this individual is the goal of the present study. Specifically, we assess whether such individual differences stem from differences in domain-general psychoacoustic processes or, rather, from differences in specific speech perception abilities.

Learning and Individual Differences, 2012

ABSTRACT The extent to which the phonetic system of a second language is mastered varies across i... more ABSTRACT The extent to which the phonetic system of a second language is mastered varies across individuals. The present study evaluates the pattern of individual differences in late bilinguals across different phonological processes. Fifty-five late Dutch-English bilinguals were tested on their ability to perceive a difficult L2 speech contrast (the English /æ/-/ε/ contrast) in three different tasks: A categorization task, a word identification task and a lexical decision task. As a group, L2 listeners were less accurate than native listeners. However, at the individual level, almost half of the L2 listeners scored within the native range in the categorization task whereas a small percentage scored within the native range in the identification and lexical decision tasks. These results show that L2 listeners' performance crucially depends on the nature of the task, with higher L2 listener accuracy on an acoustic-phonetic analysis task than on tasks involving lexical processes. These findings parallel previous results for early bilinguals, where the pattern of performance was consistent with the processing hierarchy proposed by different models of speech perception. The results indicate that the analysis of patterns of non-native performance can provide important insights concerning the architecture of the speech perception system and the issue of language learnability.

Language Learning, 2012

ABSTRACT In the process of language learning, individuals must acquire different types of linguis... more ABSTRACT In the process of language learning, individuals must acquire different types of linguistic knowledge, such as the sounds of the language (phonemes), how these may be combined to form words (phonotactics), and morphological rules. Early and late bilinguals tend to perform like natives on second language phonological tasks that involve pre-lexical processes (e.g., categorization or identification of isolate phonemes) but their performance decreases when the tasks tap into lexical processes (e.g., accessing to the lexicon storage and selecting the appropiate words). This graded performance across phonological processes is consistent with the processing hierarchy proposed by different models of (native) speech perception. The relation between the first and second languages is further evidenced by the correlation between native and non-native phoneme discrimination of both early and late bilinguals. This correlation provides evidence that individual differences in the command of non-native sounds are caused by a language-specific capability. We propose that the study of second language processes combined with the assessment of individual differences is a relevant field for the understanding of the speech perception architecture.

Journal of Cognitive Neuroscience, 2006

& Performance-based studies on the psychological nature of linguistic competence can conceal sign... more & Performance-based studies on the psychological nature of linguistic competence can conceal significant differences in the brain processes that underlie native versus nonnative knowledge of language. Here we report results from the brain activity of very proficient early bilinguals making a lexical decision task that illustrates this point. Two groups of Spanish-Catalan early bilinguals (Spanish-dominant and Catalan-dominant) were asked to decide whether a given form was a Catalan word or not. The nonwords were based on real words, with one vowel changed. In the experimental stimuli, the vowel change involved a Catalan-specific contrast that previous research had shown to be difficult for Spanish natives to perceive. In the control stimuli, the vowel switch involved contrasts common to Spanish and Catalan. The results indicated that the groups of bilinguals did not differ in their behavioral and event-related brain potential measurements for the control stimuli; both groups made very few errors and showed a larger N400 component for control nonwords than for control words. However, significant differences were observed for the experimental stimuli across groups: Specifically, Spanish-dominant bilinguals showed great difficulty in rejecting experimental nonwords. Indeed, these participants not only showed very high error rates for these stimuli, but also did not show an error-related negativity effect in their erroneous nonword decisions. However, both groups of bilinguals showed a larger correctrelated negativity when making correct decisions about the experimental nonwords. The results suggest that although some aspects of a second language system may show a remarkable lack of plasticity (like the acquisition of some foreign contrasts), first-language representations seem to be more dynamic in their capacity of adapting and incorporating new information. &