The development of tone discrimination in infancy: Evidence from a cross-linguistic, multi-lab report.

We report the findings of a multi-language and multi-lab investigation of young infants' ability to discriminate lexical tones as a function of their native language, age and language experience, as well as of tone properties. Given the high prevalence of lexical tones across human languages, understanding lexical tone acquisition is fundamental for comprehensive theories of language learning. While there are some similarities between the developmental course of lexical tone perception and that of vowels and consonants, findings for lexical tones tend to vary greatly across different laboratories. To reconcile these differences and to assess the developmental trajectory of native and non-native perception of tone contrasts, this study employed a single experimental paradigm with the same two pairs of Cantonese tone contrasts (perceptually similar vs. distinct) across 13 laboratories in Asia-Pacific, Europe and North-America testing 5-, 10- and 17-month-old monolingual (tone, pitch-accent, non-tone) and bilingual (tone/non-tone, non-tone/non-tone) infants. Across the age range and language backgrounds, infants who were not exposed to Cantonese showed robust discrimination of the two non-native lexical tone contrasts. Contrary to this overall finding, the statistical model assessing native discrimination by Cantonese-learning infants failed to yield significant effects. These findings indicate that lexical tone sensitivity is maintained from 5 to 17 months in infants acquiring tone and non-tone languages, challenging the generalisability of the existing theoretical accounts of perceptual narrowing in the first months of life. RESEARCH HIGHLIGHTS: This is a multi-language and multi-lab investigation of young infants' ability to discriminate lexical tones. This study included data from 13 laboratories testing 5-, 10-, and 17-month-old monolingual (tone, pitch-accent, non-tone) and bilingual (tone/non-tone, non-tone/non-tone) infants. Overall, infants discriminated a perceptually similar and a distinct non-native tone contrast, although there was no evidence of a native tone-language advantage in discrimination. These results demonstrate maintenance of tone discrimination throughout development.

Noun and Verb Lexicons Differentially Predict Later Grammatical Development in Mandarin-Speaking Children With and Without Late Language Emergence.

PURPOSE: The current investigation evaluated the extent to which early noun, verb, and adjective lexicon sizes predicted later grammatical outcomes in Mandarin-speaking children with and without late language emergence (LLE) using a parent report. METHOD: In Study 1, the parents of 24 Mandarin-speaking children with typical language filled out the toddler version of Mandarin-Chinese Communicative Development Inventory-Taiwan (MCDI-T) when these children were 24 and 36 months old. In Study 2, the parents of 23 children with LLE completed the same form when these children were 24, 36, and 48 months old. Noun, verb, and adjective lexicon sizes and grammatical complexity scores were computed from the MCDI-T form for each child. RESULTS: Study 1 showed that verb lexicon size, but not noun or adjective lexicon size, at 24 months predicted grammatical complexity scores at 36 months for children with typical language. Study 2 revealed that noun lexicon size, but not verb or adjective lexicon size, at 24 months predicted grammatical complexity scores at 36 months for children with LLE. Noun lexicon size at 36 months was also the only significant predictor for grammatical complexity scores at 48 months in children with LLE. CONCLUSIONS: Noun and verb lexicon size differentially predicted later grammatical outcomes in young Mandarin-speaking children with and without LLE. The finding suggested that children with LLE may have approached grammatical learning differently from their typical peers due to the small verb lexicon size in the early phase of language development.

English and Mandarin native speakers' cue-weighting of lexical stress: Results from MMN and LDN.

Past research on how listeners weight stress cues such as pitch, duration and intensity has reported two inconsistent patternss: listeners' weighting conforms to 1) their native language experience (e.g., language rhythmicity, lexical tone), and 2) a general "iambic-trochaic law" (ITL), favouring innate sound groupings in cue perception. This study aims to tease apart the above effects by investigating the weighting of pitch, duration and intensity cues in stress-timed (Australian English) and non-stress-timed and tonal (Taiwan Mandarin) language speaking adults using a mismatch negativity (MMN) multi-feature paradigm. Results show effects that can be explained by language-specific rhythmic influence, but only partially by the ITL. Moreover, these findings revealed cross-linguistic differences indexed by both MMN and late discriminative negativity (LDN) responses at cue and syllable position levels, and thus call for more sophisticated perspectives for existing cue-weighting models.

Temporal stability of parent-reported behavior problems in late talkers over 2 years: a prospective case-control study from toddlerhood to preschool age.

BACKGROUND: Late talking (LT) in toddlers is a risk factor for language weakness that may interfere with the development of using language to regulate behavior and emotion and contribute to the development of behavior problems from early childhood. This study examined the temporal stability of parent-reported behavior problems among Mandarin-speaking LT toddlers from ages 2 to 4 in Taiwan. METHODS: Thirty-one LT and 31 typical language development (TLD) toddlers were assessed for their vocabulary production at age 2 with the Words and Sentences Forms of the MacArthur-Bates Communicative Developmental Inventories Toddler Form (Taiwan version). Additionally, participants' receptive and expressive language abilities were assessed using the receptive and expressive language subscales of the Bayley Scales of Infant and Toddler Development, Third Edition. At age 4, the Child Language Disorder Scale-Revised was applied and included the two core subtests for auditory comprehension and expressive communication. At ages 2 and 4 years, behavior problems were assessed with the Child Behavior Checklist. RESULTS: There was a higher percentage of participants with persistent behavior problems among LT toddlers than among TLD toddlers. Moreover, toddlers with larger vocabularies were less likely to develop withdrawal behaviors by preschool age. CONCLUSIONS: This study supported the temporal stability of parent-reported behavior problems among LT toddlers across early childhood. Early identification of and intervention for behavior problems associated with LT in toddlerhood is essential to alleviate their behavior problems later in preschool years.

Behavioral problems of Mandarin-speaking late-talking toddlers and preschool aged children: A prospective case-control study in Taiwan.

This study aimed to examine whether Mandarin-speaking late-talking (LT) toddlers have a higher incidence of behavioral problems than typical language developing (TLD) children in toddlerhood and at preschool age from a community sample in Taiwan.This prospective case-control study comprised 32 LT and 32 TLD toddlers. Participants' parents provided reports about their children at 2 and 4 years using the Child Behaviors Checklist, a component of the Achenbach System of Empirically Based Assessment.The results indicated that compared to the TLD group, a higher percentage of the LT group was at risk of behavioral problems at both two and four years. Similarly, the chance of internalizing problems was higher in the LT group than the TLD group at both ages.The findings indicated that LT toddlers are at risk for behavioral problems not only in toddlerhood, but also at preschool age. Thus, it is crucial to identify LT toddlers with behavioral problems and enroll them in early developmental evaluation programs in their communities and also include them in early intervention programs if necessary. In addition, the underlying mechanism of the association between language delay and behavioral problems in children needs to be longitudinally explored from a young age.

Discrimination and identification of lexical tones and consonants in Mandarin-speaking children using cochlear implants.

Mandarin-speaking adults using cochlear implants (CI) experience more difficulties in perceiving lexical tones than consonants. This problem may result from the fact that CIs provide relatively sufficient temporal envelope information for consonant perception in quiet environments, but do not convey the fine spectro-temporal information considered to be necessary for accurate pitch perception. Another possibility is that Mandarin speakers with post-lingual hearing loss have developed language-specific use of these acoustic cues, impeding lexical tone processing under CI conditions. To investigate this latter hypothesis, syllable discrimination and word identification abilities for Mandarin consonants (place and manner) and lexical-tone contrasts (tones 1 vs 3 and 1 vs 2) were measured in 15 Mandarin-speaking children using CIs and age-matched children with normal hearing (NH). In the discrimination task, only children using CIs exhibited significantly lower scores for consonant place contrasts compared to other contrasts, including lexical tones. In the word identification task, children using CIs showed lower performance for all contrasts compared to children with NH, but they both showed specific difficulties with tone 1 vs 2 contrasts. This study suggests that Mandarin-speaking children using CIs are able to discriminate and identify lexical tones and, perhaps more surprisingly, have more difficulties when discriminating consonants.

Perceptual Improvement of Lexical Tones in Infants: Effects of Tone Language Experience.

To learn words in a tonal language, tone-language learners should not only develop better abilities for perceiving consonants and vowels, but also for lexical tones. The divergent trend of enhancing sensitivity to native phonetic contrasts and reduced sensitivity to non-native phonetic contrast is theoretically essential to evaluate effects of listening to an ambient language on speech perception development. The loss of sensitivity in discriminating lexical tones among non-tonal language-learning infants was apparent between 6 and 12 months of age, but only few studies examined trends of differentiating native lexical tones in infancy. The sensitivity in discriminating lexical tones among 6-8 and 10-12 month-old Mandarin-learning infants (n = 120) was tested in Experiment 1 using three lexical tone contrasts of Mandarin. Facilitation of linguistic experience was shown in the tonal contrast (Tone 1 vs. 3), but both age groups performed similar in the other two tonal contrasts (Tone 2 vs. 4; Tone 2 vs. 3). In Experiment 2, 6-8 and 10-12 month-old Mandarin-learning infants (n = 90) were tested with tonal contrasts that have pitch contours either similar to or inverse from lexical tones in Mandarin, and perceptual improvement was shown only in a tonal contrast with familiar pitch contours (i.e., Tone 1 vs. 3). In Experiment 3, 6-8 and 10-12 month-old English-learning infants (n = 40) were tested with Tone 1 vs. 3 contrast of Mandarin and showed an improvement in the perception of non-native lexical tones. This study reveals that tone-language learning infants develop more accurate representations of lexical tones around their first birthday, and the results of both tone and non-tone language-learning infants imply that the rate of development depends on listening experience and the acoustical salience of specific tone contrasts.

Speech Perception Deficits in Mandarin-Speaking School-Aged Children with Poor Reading Comprehension.

Previous studies have shown that children learning alphabetic writing systems who have language impairment or dyslexia exhibit speech perception deficits. However, whether such deficits exist in children learning logographic writing systems who have poor reading comprehension remains uncertain. To further explore this issue, the present study examined speech perception deficits in Mandarin-speaking children with poor reading comprehension. Two self-designed tasks, consonant categorical perception task and lexical tone discrimination task were used to compare speech perception performance in children (n = 31, age range = 7;4-10;2) with poor reading comprehension and an age-matched typically developing group (n = 31, age range = 7;7-9;10). Results showed that the children with poor reading comprehension were less accurate in consonant and lexical tone discrimination tasks and perceived speech contrasts less categorically than the matched group. The correlations between speech perception skills (i.e., consonant and lexical tone discrimination sensitivities and slope of consonant identification curve) and individuals' oral language and reading comprehension were stronger than the correlations between speech perception ability and word recognition ability. In conclusion, the results revealed that Mandarin-speaking children with poor reading comprehension exhibit less-categorized speech perception, suggesting that imprecise speech perception, especially lexical tone perception, is essential to account for reading learning difficulties in Mandarin-speaking children.

Developmental changes in brain response to speech perception in late-talking children: A longitudinal MMR study.

This study used a longitudinal design to examine the development of mismatch responses (MMRs) to Mandarin lexical tones, an index of neural speech discriminative responses, in late talkers and typical controls at 3, 5, and 6 years of age. Lexical tones are phonetic suprasegments that distinguish the lexical meanings of syllables in tonal languages. The 2 year-old late talkers were later divided into persistent language delay and late bloomer groups according to their performance on standardized language tests at 4 years. Results showed that children with persistent language delay demonstrated more positive mismatch responses than the typical controls at 3 years of age. At the age of 5, no group difference were found in the amplitude of MMRs, but the maturation of MMRs could be observed in the change of topography, with more prominent negative response in the frontal sites only in the typical group. Correlations were found between the index of MMRs at 3 years and children's language performance outcome at 6 years. Our results indicate that the development of fine-grained tone representations is delayed in late-talking children between 3 and 5 years and may be one of the underlying mechanisms which associated with later language performance.

The perception of speech modulation cues in lexical tones is guided by early language-specific experience.

A number of studies showed that infants reorganize their perception of speech sounds according to their native language categories during their first year of life. Still, information is lacking about the contribution of basic auditory mechanisms to this process. This study aimed to evaluate when native language experience starts to noticeably affect the perceptual processing of basic acoustic cues [i.e., frequency-modulation (FM) and amplitude-modulation information] known to be crucial for speech perception in adults. The discrimination of a lexical-tone contrast (rising versus low) was assessed in 6- and 10-month-old infants learning either French or Mandarin using a visual habituation paradigm. The lexical tones were presented in two conditions designed to either keep intact or to severely degrade the FM and fine spectral cues needed to accurately perceive voice-pitch trajectory. A third condition was designed to assess the discrimination of the same voice-pitch trajectories using click trains containing only the FM cues related to the fundamental-frequency (F0) in French- and Mandarin-learning 10-month-old infants. Results showed that the younger infants of both language groups and the Mandarin-learning 10-month-olds discriminated the intact lexical-tone contrast while French-learning 10-month-olds failed. However, only the French 10-month-olds discriminated degraded lexical tones when FM, and thus voice-pitch cues were reduced. Moreover, Mandarin-learning 10-month-olds were found to discriminate the pitch trajectories as presented in click trains better than French infants. Altogether, these results reveal that the perceptual reorganization occurring during the first year of life for lexical tones is coupled with changes in the auditory ability to use speech modulation cues.

Emotional prosody perception and its association with pragmatic language in school-aged children with high-function autism.

Emotional prosody perception is essential for social communication, but it is still an open issue whether children with high-function autism (HFA) exhibit any prosodic perception deficits or experience selective impairments in recognizing the prosody of positive emotions. Moreover, the associations between prosody perception, pragmatic language, and social adaptation in children with HFA have not been fully explored. This study investigated whether emotional prosody perception for words and sentences in children with HFA (n=25, 6-11 years of age) differed from age-matched, typically developing children (TD, n=25) when presented with an emotional prosody identification task. The Children's Communication Checklist and Vineland Adaptive Behavior Scale were used to assess pragmatic and social adaption abilities. Results show that children with HFA performed poorer than TD children in identifying happy prosody in both emotionally neutral and relevant utterances. In contrast, children with HFA did not exhibit any deficits in identifying sad and angry prosody. Results of correlation analyses revealed a positive association between happy prosody identification and pragmatic function. The findings indicate that school-aged children with HFA experience difficulties in recognizing happy prosody, and that this limitation in prosody perception is associated with their pragmatic and social adaption performances.

The role of spectro-temporal fine structure cues in lexical-tone discrimination for French and Mandarin listeners.

The role of spectro-temporal modulation cues in conveying tonal information for lexical tones was assessed in native-Mandarin and native-French adult listeners using a lexical-tone discrimination task. The fundamental frequency (F0) of Thai tones was either degraded using an 8-band vocoder that reduced fine spectral details and frequency-modulation cues, or extracted and used to modulate the F0 of click trains. Mandarin listeners scored lower than French listeners in the discrimination of vocoded lexical tones. For click trains, Mandarin listeners outperformed French listeners. These preliminary results suggest that the perceptual weight of the fine spectro-temporal modulation cues conveying F0 information is enhanced for adults speaking a tonal language.

Developmental changes in mismatch responses to mandarin consonants and lexical tones from early to middle childhood.

The purpose of this study was to use mismatch responses (MMRs) to explore the dynamic changes of Mandarin speech perception abilities from early to middle childhood. Twenty preschoolers, 18 school-aged children, and 26 adults participated in this study. Two sets of synthesized speech stimuli varying in Mandarin consonant (alveolo-palatal affricate vs. fricative) and lexical tone features (rising vs. contour tone) were used to examine the developmental course of speech perception abilities. The results indicated that only the adult group demonstrated typical early mismatch negativity (MMN) responses, suggesting that the ability to discriminate specific speech cues in Mandarin consonant and lexical tone is a continuing process in preschool- and school-aged children. Additionally, distinct MMR patterns provided evidence indicating diverse developmental courses to different speech characteristics. By incorporating data from the two speech conditions, we propose using MMR profiles consisting of mismatch negativity (MMN), positive mismatch response (p-MMR), and late discriminative negativity (LDN) as possible brain indices to investigate speech perception development.

Linking brain-wide multivoxel activation patterns to behaviour: Examples from language and math.

A key goal of cognitive neuroscience is to find simple and direct connections between brain and behaviour. However, fMRI analysis typically involves choices between many possible options, with each choice potentially biasing any brain-behaviour correlations that emerge. Standard methods of fMRI analysis assess each voxel individually, but then face the problem of selection bias when combining those voxels into a region-of-interest, or ROI. Multivariate pattern-based fMRI analysis methods use classifiers to analyse multiple voxels together, but can also introduce selection bias via data-reduction steps as feature selection of voxels, pre-selecting activated regions, or principal components analysis. We show here that strong brain-behaviour links can be revealed without any voxel selection or data reduction, using just plain linear regression as a classifier applied to the whole brain at once, i.e. treating each entire brain volume as a single multi-voxel pattern. The brain-behaviour correlations emerged despite the fact that the classifier was not provided with any information at all about subjects' behaviour, but instead was given only the neural data and its condition-labels. Surprisingly, more powerful classifiers such as a linear SVM and regularised logistic regression produce very similar results. We discuss some possible reasons why the very simple brain-wide linear regression model is able to find correlations with behaviour that are as strong as those obtained on the one hand from a specific ROI and on the other hand from more complex classifiers. In a manner which is unencumbered by arbitrary choices, our approach offers a method for investigating connections between brain and behaviour which is simple, rigorous and direct.

Quantifying the adequacy of neural representations for a cross-language phonetic discrimination task: prediction of individual differences.

In order for stimuli to be perceptually discriminable, their representations in the brain must be distinct. Investigating the task of discriminating the syllables /ra/ and /la/, we hypothesized that the more distinct a person's neural representations of those sounds were, the better their behavioral ability to discriminate them would be. Standard neuroimaging approaches are ill-suited to testing this hypothesis as they have problems differentiating between neural representations spatially intermingled within the same brain area. We therefore performed multi-voxel pattern-based analysis of the functional magnetic resonance imaging (fMRI) activity elicited by these syllables, in native speakers of English and Japanese. In right primary auditory cortex, the statistical separability of these fMRI patterns predicted subjects' behavioral ability to tell the sounds apart, not only across groups but also across individuals. This opens up a new approach for identifying neural representations and for quantifying their task suitability.

Age-related changes in acoustic modifications of Mandarin maternal speech to preverbal infants and five-year-old children: a longitudinal study.

ABSTRACTAcoustic-phonetic exaggeration of infant-directed speech (IDS) is well documented, but few studies address whether these features are modified with a child's age. Mandarin-speaking mothers were recorded while addressing an adult and their child at two ages (0 ; 7-1 ; 0 and 5 ; 0) to examine the acoustic-phonetic differences between IDS and child-directed speech (CDS). CDS exhibits an exaggeration pattern resembling that of IDS - expanded vowel space, longer vowels, higher pitch and greater lexical tone differences - when compared to ADS. Longitudinal analysis demonstrated that the extent of acoustic exaggeration is significantly smaller in CDS than in IDS. Age-related changes in maternal speech provide some support for the hypothesis that mothers adjust their speech directed toward children as a function of the child's language ability.

Acoustic analysis of lexical tone in Mandarin infant-directed speech.

Using Mandarin Chinese, a "tone language" in which the pitch contours of syllables differentiate words, the authors examined the acoustic modifications of infant-directed speech (IDS) at the syllable level to test 2 hypotheses: (a) the overall increase in pitch and intonation contour that occurs in IDS at the phrase level would not distort lexical pitch at the syllable level and (b) IDS provides exaggerates cues to lexical tones. Sixteen Mandarin-speaking mothers were recorded while addressing their infants and addressing an adult. The results indicate that IDS does not distort the acoustic cues that are essential to word meaning at the syllable level; evidence of exaggeration of the acoustic differences in IDS was observed, extending previous findings of phonetic exaggeration to the lexical level.

Perception of native and non-native affricate-fricative contrasts: cross-language tests on adults and infants.

Previous studies have shown improved sensitivity to native-language contrasts and reduced sensitivity to non-native phonetic contrasts when comparing 6-8 and 10-12-month-old infants. This developmental pattern is interpreted as reflecting the onset of language-specific processing around the first birthday. However, generalization of this finding is limited by the fact that studies have yielded inconsistent results and that insufficient numbers of phonetic contrasts have been tested developmentally; this is especially true for native-language phonetic contrasts. Three experiments assessed the effects of language experience on affricate-fricative contrasts in a cross-language study of English and Mandarin adults and infants. Experiment 1 showed that English-speaking adults score lower than Mandarin-speaking adults on Mandarin alveolo-palatal affricate-fricative discrimination. Experiment 2 examined developmental change in the discrimination of this contrast in English- and Mandarin-leaning infants between 6 and 12 months of age. The results demonstrated that native-language performance significantly improved with age while performance on the non-native contrast decreased. Experiment 3 replicated the perceptual improvement for a native contrast: 6-8 and 10-12-month-old English-learning infants showed a performance increase at the older age. The results add to our knowledge of the developmental patterns of native and non-native phonetic perception.

The effect of reduced vowel working space on speech intelligibility in Mandarin-speaking young adults with cerebral palsy.

The purpose of this study was to examine the effect of reduced vowel working space on dysarthric talkers' speech intelligibility using both acoustic and perceptual approaches. In experiment 1, the acoustic-perceptual relationship between vowel working space area and speech intelligibility was examined in Mandarin-speaking young adults with cerebral palsy. Subjects read aloud 18 bisyllabic words containing the vowels /i/, /a/, and /u/ using their normal speaking rate. Each talker's words were identified by three normal listeners. The percentage of correct vowel and word identification were calculated as vowel intelligibility and word intelligibility, respectively. Results revealed that talkers with cerebral palsy exhibited smaller vowel working space areas compared to ten age-matched controls. The vowel working space area was significantly correlated with vowel intelligibility (r=0.632, p<0.005) and with word intelligibility (r=0.684, p<0.005). Experiment 2 examined whether tokens of expanded vowel working spaces were perceived as better vowel exemplars and represented with greater perceptual spaces than tokens of reduced vowel working spaces. The results of the perceptual experiment support this prediction. The distorted vowels of talkers with cerebral palsy compose a smaller acoustic space that results in shrunken intervowel perceptual distances for listeners.

Speech perception in infancy predicts language development in the second year of life: a longitudinal study.

Infants' early phonetic perception is hypothesized to play an important role in language development. Previous studies have not assessed this potential link in the first 2 years of life. In this study, speech discrimination was measured in 6-month-old infants using a conditioned head-turn task. At 13, 16, and 24 months of age, language development was assessed in these same children using the MacArthur Communicative Development Inventory. Results demonstrated significant correlations between speech perception at 6 months of age and later language (word understanding, word production, phrase understanding). The finding that speech perception performance at 6 months predicts language at 2 years supports the idea that phonetic perception may play an important role in language acquisition.