Atypical low-frequency cortical encoding of speech identifies children with developmental dyslexia.

Slow cortical oscillations play a crucial role in processing the speech amplitude envelope, which is perceived atypically by children with developmental dyslexia. Here we use electroencephalography (EEG) recorded during natural speech listening to identify neural processing patterns involving slow oscillations that may characterize children with dyslexia. In a story listening paradigm, we find that atypical power dynamics and phase-amplitude coupling between delta and theta oscillations characterize dyslexic versus other child control groups (typically-developing controls, other language disorder controls). We further isolate EEG common spatial patterns (CSP) during speech listening across delta and theta oscillations that identify dyslexic children. A linear classifier using four delta-band CSP variables predicted dyslexia status (0.77 AUC). Crucially, these spatial patterns also identified children with dyslexia when applied to EEG measured during a rhythmic syllable processing task. This transfer effect (i.e., the ability to use neural features derived from a story listening task as input features to a classifier based on a rhythmic syllable task) is consistent with a core developmental deficit in neural processing of speech rhythm. The findings are suggestive of distinct atypical neurocognitive speech encoding mechanisms underlying dyslexia, which could be targeted by novel interventions.

Effects of environmental diversity on exploration and learning: The case of bilingualism.

Bilingual environments provide a commonplace example of increased complexity and uncertainty. Learning multiple languages entails mastery of a larger and more variable range of sounds, words, syntactic structures, pragmatic conventions, and more complex mapping of linguistic information to objects in the world. Recent research suggests that bilingual learners demonstrate fundamental variation in how they explore and learn from their environment, which may derive from this increased complexity. In particular, the increased complexity and variability of bilingual environments may broaden the focus of learners' attention, laying a different attentional foundation for learning. In this review, we introduce a novel framework, with accompanying empirical evidence, for understanding how early learners may adapt to a more complex environment, drawing on bilingualism as an example. Three adaptations, each relevant to the demands of abstracting structure from a complex environment, are introduced. Each adaptation is discussed in the context of empirical evidence attesting to shifts in basic psychological processes in bilingual learners. This evidence converges on the notion that bilingual learners may explore their environment more broadly. Downstream consequences of broader sampling for perception and learning are discussed. Finally, recommendations for future research to expand the scientific narrative on the impact of diverse environments on learning are provided. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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.

Everyday language input and production in 1,001 children from six continents.

Language is a universal human ability, acquired readily by young children, who otherwise struggle with many basics of survival. And yet, language ability is variable across individuals. Naturalistic and experimental observations suggest that children's linguistic skills vary with factors like socioeconomic status and children's gender. But which factors really influence children's day-to-day language use? Here, we leverage speech technology in a big-data approach to report on a unique cross-cultural and diverse data set: >2,500 d-long, child-centered audio-recordings of 1,001 2- to 48-mo-olds from 12 countries spanning six continents across urban, farmer-forager, and subsistence-farming contexts. As expected, age and language-relevant clinical risks and diagnoses predicted how much speech (and speech-like vocalization) children produced. Critically, so too did adult talk in children's environments: Children who heard more talk from adults produced more speech. In contrast to previous conclusions based on more limited sampling methods and a different set of language proxies, socioeconomic status (operationalized as maternal education) was not significantly associated with children's productions over the first 4 y of life, and neither were gender or multilingualism. These findings from large-scale naturalistic data advance our understanding of which factors are robust predictors of variability in the speech behaviors of young learners in a wide range of everyday contexts.

Phonetic accommodation in non-native directed speech supports L2 word learning and pronunciation.

This study assessed whether Non-native Directed Speech (NNDS) facilitates second language (L2) learning, specifically L2 word learning and production. Spanish participants (N = 50) learned novel English words, presented either in NNDS or Native-Directed Speech (NDS), in two tasks: Recognition and Production. Recognition involved matching novel objects to their labels produced in NNDS or NDS. Production required participants to pronounce these objects' labels. The novel words contained English vowel contrasts, which approximated Spanish vowel categories more (/i-ɪ/) or less (/ʌ-æ/). Participants in the NNDS group exhibited faster recognition of novel words, improved learning, and produced the /i-ɪ/ contrast with greater distinctiveness in comparison to the NDS group. Participants' ability to discriminate the target vowel contrasts was also assessed before and after the tasks, with no improvement detected in the two groups. These findings support the didactic assumption of NNDS, indicating the relevance of the phonetic adaptations in this register for successful L2 acquisition.

Seeing a Talking Face Matters: Gaze Behavior and the Auditory-Visual Speech Benefit in Adults' Cortical Tracking of Infant-directed Speech.

In face-to-face conversations, listeners gather visual speech information from a speaker's talking face that enhances their perception of the incoming auditory speech signal. This auditory-visual (AV) speech benefit is evident even in quiet environments but is stronger in situations that require greater listening effort such as when the speech signal itself deviates from listeners' expectations. One example is infant-directed speech (IDS) presented to adults. IDS has exaggerated acoustic properties that are easily discriminable from adult-directed speech (ADS). Although IDS is a speech register that adults typically use with infants, no previous neurophysiological study has directly examined whether adult listeners process IDS differently from ADS. To address this, the current study simultaneously recorded EEG and eye-tracking data from adult participants as they were presented with auditory-only (AO), visual-only, and AV recordings of IDS and ADS. Eye-tracking data were recorded because looking behavior to the speaker's eyes and mouth modulates the extent of AV speech benefit experienced. Analyses of cortical tracking accuracy revealed that cortical tracking of the speech envelope was significant in AO and AV modalities for IDS and ADS. However, the AV speech benefit [i.e., AV > (A + V)] was only present for IDS trials. Gaze behavior analyses indicated differences in looking behavior during IDS and ADS trials. Surprisingly, looking behavior to the speaker's eyes and mouth was not correlated with cortical tracking accuracy. Additional exploratory analyses indicated that attention to the whole display was negatively correlated with cortical tracking accuracy of AO and visual-only trials in IDS. Our results underscore the nuances involved in the relationship between neurophysiological AV speech benefit and looking behavior.

Bilingual infants readily orient to novel visual stimuli.

Bilingualism has been shown to modify infants' responses in a range of domains. In particular, early bilingual experience is associated with greater flexibility and openness in infant perception and learning. In this study, we investigated whether bilingual infants demonstrate more fundamental differences in how they explore their environment in ways that could contribute to greater openness. Specifically, we investigated whether bilingual infants orient more rapidly to new information. Capitalizing on a classic paradigm by Fantz (1964), monolingual and bilingual infants (5-6 months and 8-9 months) were simultaneously presented with familiar and novel stimuli. As they received increased exposure to the familiar and novel stimuli, monolingual infants demonstrated a null preference, followed by a novelty preference, as previously evidenced in Fantz's study. In contrast, an orientation toward novelty emerged more readily in bilingual infants. Characteristics of a bilingual environment that may modulate the allocation of attention toward novelty are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Effects of maternal depression on maternal responsiveness and infants' expressive language abilities.

High levels of maternal responsiveness are associated with healthy cognitive and emotional development in infants. However, depression and anxiety can negatively impact individual mothers' responsiveness levels and infants' expressive language abilities. Australian mother-infant dyads (N = 48) participated in a longitudinal study examining the effect of maternal responsiveness (when infants were 9- and 12-months), and maternal depression and anxiety symptoms on infant vocabulary size at 18-months. Global maternal responsiveness ratings were stronger predictors of infants' vocabulary size than levels of depression and anxiety symptoms. However, depression levels moderated the effect of maternal responsiveness on vocabulary size. These results highlight the importance of screening for maternal responsiveness-in addition to depression-to identify infants who may be at developmental risk. Also, mothers with elevated depression need support to first reduce their symptoms so that improvements in their responsiveness have the potential to be protective for their infant's language acquisition.

Seeing a talking face matters: Infants' segmentation of continuous auditory-visual speech.

Visual speech cues from a speaker's talking face aid speech segmentation in adults, but despite the importance of speech segmentation in language acquisition, little is known about the possible influence of visual speech on infants' speech segmentation. Here, to investigate whether there is facilitation of speech segmentation by visual information, two groups of English-learning 7-month-old infants were presented with continuous speech passages, one group with auditory-only (AO) speech and the other with auditory-visual (AV) speech. Additionally, the possible relation between infants' relative attention to the speaker's mouth versus eye regions and their segmentation performance was examined. Both the AO and the AV groups of infants successfully segmented words from the continuous speech stream, but segmentation performance persisted for longer for infants in the AV group. Interestingly, while AV group infants showed no significant relation between the relative amount of time spent fixating the speaker's mouth versus eyes and word segmentation, their attention to the mouth was greater than that of AO group infants, especially early in test trials. The results are discussed in relation to the possible pathways through which visual speech cues aid speech perception.

Impaired neural entrainment to low frequency amplitude modulations in English-speaking children with dyslexia or dyslexia and DLD.

Neural synchronization to amplitude-modulated noise at three frequencies (2 Hz, 5 Hz, 8 Hz) thought to be important for syllable perception was investigated in English-speaking school-aged children. The theoretically-important delta-band (∼2Hz, stressed syllable level) was included along with two syllable-level rates. The auditory steady state response (ASSR) was recorded using EEG in 36 7-to-12-year-old children. Half of the sample had either dyslexia or dyslexia and DLD (developmental language disorder). In comparison to typically-developing children, children with dyslexia or with dyslexia and DLD showed reduced ASSRs for 2 Hz stimulation but similar ASSRs at 5 Hz and 8 Hz. These novel data for English ASSRs converge with prior data suggesting that children with dyslexia have atypical synchrony between brain oscillations and incoming auditory stimulation at âˆ¼ 2 Hz, the rate of stressed syllable production across languages. This atypical synchronization likely impairs speech processing, phonological processing, and possibly syntactic processing, as predicted by Temporal Sampling theory.

Language specificity in cortical tracking of speech rhythm at the mora, syllable, and foot levels.

Recent research shows that adults' neural oscillations track the rhythm of the speech signal. However, the extent to which this tracking is driven by the acoustics of the signal, or by language-specific processing remains unknown. Here adult native listeners of three rhythmically different languages (English, French, Japanese) were compared on their cortical tracking of speech envelopes synthesized in their three native languages, which allowed for coding at each of the three language's dominant rhythmic unit, respectively the foot (2.5 Hz), syllable (5 Hz), or mora (10 Hz) level. The three language groups were also tested with a sequence in a non-native language, Polish, and a non-speech vocoded equivalent, to investigate possible differential speech/nonspeech processing. The results first showed that cortical tracking was most prominent at 5 Hz (syllable rate) for all three groups, but the French listeners showed enhanced tracking at 5 Hz compared to the English and the Japanese groups. Second, across groups, there were no differences in responses for speech versus non-speech at 5 Hz (syllable rate), but there was better tracking for speech than for non-speech at 10 Hz (not the syllable rate). Together these results provide evidence for both language-general and language-specific influences on cortical tracking.

The Acoustic Features and Didactic Function of Foreigner-Directed Speech: A Scoping Review.

PURPOSE: This scoping review considers the acoustic features of a clear speech register directed to nonnative listeners known as foreigner-directed speech (FDS). We identify vowel hyperarticulation and low speech rate as the most representative acoustic features of FDS; other features, including wide pitch range and high intensity, are still under debate. We also discuss factors that may influence the outcomes and characteristics of FDS. We start by examining accommodation theories, outlining the reasons why FDS is likely to serve a didactic function by helping listeners acquire a second language (L2). We examine how this speech register adapts to listeners' identities and linguistic needs, suggesting that FDS also takes listeners' L2 proficiency into account. To confirm the didactic function of FDS, we compare it to other clear speech registers, specifically infant-directed speech and Lombard speech. CONCLUSIONS: Our review reveals that research has not yet established whether FDS succeeds as a didactic tool that supports L2 acquisition. Moreover, a complex set of factors determines specific realizations of FDS, which need further exploration. We conclude by summarizing open questions and indicating directions and recommendations for future research.

Seeing a talking face matters: The relationship between cortical tracking of continuous auditory-visual speech and gaze behaviour in infants, children and adults.

An auditory-visual speech benefit, the benefit that visual speech cues bring to auditory speech perception, is experienced from early on in infancy and continues to be experienced to an increasing degree with age. While there is both behavioural and neurophysiological evidence for children and adults, only behavioural evidence exists for infants - as no neurophysiological study has provided a comprehensive examination of the auditory-visual speech benefit in infants. It is also surprising that most studies on auditory-visual speech benefit do not concurrently report looking behaviour especially since the auditory-visual speech benefit rests on the assumption that listeners attend to a speaker's talking face and that there are meaningful individual differences in looking behaviour. To address these gaps, we simultaneously recorded electroencephalographic (EEG) and eye-tracking data of 5-month-olds, 4-year-olds and adults as they were presented with a speaker in auditory-only (AO), visual-only (VO), and auditory-visual (AV) modes. Cortical tracking analyses that involved forward encoding models of the speech envelope revealed that there was an auditory-visual speech benefit [i.e., AV > (A + V)], evident in 5-month-olds and adults but not 4-year-olds. Examination of cortical tracking accuracy in relation to looking behaviour, showed that infants' relative attention to the speaker's mouth (vs. eyes) was positively correlated with cortical tracking accuracy of VO speech, whereas adults' attention to the display overall was negatively correlated with cortical tracking accuracy of VO speech. This study provides the first neurophysiological evidence of auditory-visual speech benefit in infants and our results suggest ways in which current models of speech processing can be fine-tuned.

The tone atlas of perceptual discriminability and perceptual distance: Four tone languages and five language groups.

Some prior investigations suggest that tone perception is flexible, reasonably independent of native phonology, whereas others suggest it is constrained by native phonology. We address this issue in a systematic and comprehensive investigation of adult tone perception. Sampling from diverse tone and non-tone speaking communities, we tested discrimination of the three major tone systems (Cantonese, Thai, Mandarin) that dominate the tone perception literature, in relation to native language and language experience as well as stimulus variation (tone properties, presentation order, pitch cues) using linear mixed effect modelling and multidimensional scaling. There was an overall discrimination advantage for tone language speakers and for native tones. However, language- and tone-specific effects, and presentation order effects also emerged. Thus, over and above native phonology, stimulus variation exerts a powerful influence on tone discrimination. This study provides a tone atlas, a reference guide to inform empirical studies of tone sensitivity, both retrospectively and prospectively.

Language development in infants with hearing loss: Benefits of infant-directed speech.

The majority of infants with permanent congenital hearing loss fall significantly behind their normal hearing peers in the development of receptive and expressive oral communication skills. Independent of any prosthetic intervention ("hardware") for infants with hearing loss, the social and linguistic environment ("software") can still be optimal or sub-optimal and so can exert significant positive or negative effects on speech and language acquisition, with far-reaching beneficial or adverse effects, respectively. This review focusses on the nature of the social and linguistic environment of infants with hearing loss, in particular others' speech to infants. The nature of this "infant-directed speech" and its effects on language development has been studied extensively in hearing infants but far less comprehensively in infants with hearing loss. Here, literature on the nature of infant-directed speech and its impact on the speech perception and language acquisition in infants with hearing loss is reviewed. The review brings together evidence on the little-studied effects of infant-directed speech on speech and language development in infants with hearing loss, and provides suggestions, over and above early screening and external treatment, for a natural intervention at the level of the carer-infant microcosm that may well optimize the early linguistic experiences and mitigate later adverse effects for infants born with hearing loss.

A short-form version of the Australian English Communicative Development Inventory.

Purpose: The Australian English Communicative Development Inventory (OZI) is a 558-item parent report tool for assessing language development at 12-30 months. Here, we introduce the short form (OZI-SF), a 100-item, picture-supported, online instrument with substantially lower time and literacy demands.Method: In tool development (Study 1), 95 items were drawn from the OZI to match its item distribution by age of acquisition and semantic categories. Five items were added from four other semantic categories, plus 12 gestures and six games/routines. Simulations computed OZI-SF scores from existing long-form OZI norm data, and OZI and projected OZI-SF scores were correlated. In an independent norming sample (Study 2), parents (n = 230) completed the OZI-SF for their children aged 12-30 months. Child scores were analysed by age and sex.Result: OZI-SF and OZI scores correlate highly across age and language development levels. Vocabulary scores (receptive, expressive) correlate with age and the median for girls is higher until 24 months. By 24 months, 50% of the sample combine words "often". The median time to OZI-SF completion was 12 minutes.Conclusion: Fitted percentiles permit working guidelines for typical (median) performance and lower cut-offs for children who may be behind on age-based expectations and/or at risk for a communication difficulty. The OZI-SF is a short-form of the OZI that has promise for research and clinical/educational use with Australian families.

Input quality and speech perception development in bilingual infants' first year of life.

Individual differences in infants' native phonological development have been linked to the quantity and quality of infant-directed speech (IDS). The effects of parental and infant bilingualism on this relation in 131 five- and nine-month-old monolingual and bilingual Spanish and Basque infants (72 male; 59 female; from white middle-class background) were investigated. Bilingualism did not affect the developmental trajectory of infants' native and non-native speech perception and the quality of maternal speech. In both language groups, vowel exaggeration in IDS was significantly related to speech perception skills for 9-month-olds (r = -.30), but not for 5-month-olds. This demonstrates that bilingual and monolingual caregivers provide their infants with speech input that assists their task of learning the phonological inventory of one or two languages.

Reproducibility and Interobserver Agreement of Different Thyroid Imaging and Reporting Data Systems (TIRADS).

INTRODUCTION: A number of classification systems (TIRADS) have been developed to estimate the likelihood of malignancy in thyroid nodules, but their reproducibility is yet to be assessed. We evaluated the interobserver variability and diagnostic performance of the TIRADS in Kwak's modification (Kw-TIRADS) and European TIRADS (EU-TIRADS). METHODS: Two independent specialists, blinded concerning the morphology of the nodules, evaluated ultrasound images of 153 thyroid nodules identified in 149 patients at multiple time points. RESULTS: The interobserver agreement (Cohen's κ) was 0.52 and 0.67 for Kw-TIRADS and EU-TIRADS, respectively, and rated as substantial. There were strong correlations between Kw-TIRADS and EU-TIRADS for the two observers with Spearman's coefficients of 0.731 (p = 0.00025) and 0.661 (p = 0.0012), respectively. Sensitivity of Kw-TIRADS for the diagnosis of thyroid cancer was 95-92.31% and that of EU-TIRADS was 92.31-89.74%, with specificity of about 60% for both TIRADS. CONCLUSION: Despite the wide variability in the description of single ultrasonographic features, both Kw-TIRADS and EU-TIRADS may be a useful diagnostic tool in clinical practice.

Lexical and Prosodic Pitch Modifications in Cantonese Infant-directed Speech.

The functions of acoustic-phonetic modifications in infant-directed speech (IDS) remain a question: do they specifically serve to facilitate language learning via enhanced phonemic contrasts (the hyperarticulation hypothesis) or primarily to improve communication via prosodic exaggeration (the prosodic hypothesis)? The study of lexical tones provides a unique opportunity to shed light on this, as lexical tones are phonemically contrastive, yet their primary cue, pitch, is also a prosodic cue. This study investigated Cantonese IDS and found increased intra-talker variation of lexical tones, which more likely posed a challenge to rather than facilitated phonetic learning. Although tonal space was expanded which could facilitate phonetic learning, its expansion was a function of overall intonational modifications. Similar findings were observed in speech to pets who should not benefit from larger phonemic distinction. We conclude that lexical-tone adjustments in IDS mainly serve to broadly enhance communication rather than specifically increase phonemic contrast for learners.

The effects of bilingualism on attentional processes in the first year of life.

Bilingualism is a powerful experiential factor, and its effects have been proposed to extend beyond the linguistic domain by boosting the development of executive functioning skills. Crucially, recent findings suggest that this effect can be detected in bilingual infants before their first birthday indicating that it emerges as a result of early bilingual exposure and the experience of negotiating two linguistic systems in infants' environment. However, these conclusions are based on only two research studies from the last decade (Comishen, Bialystok, & Adler, 2019; Kovács & Mehler, 2009), so to date, there is a lack of evidence regarding their replicability and generalizability. In addition, previous research does not shed light on the precise aspects of bilingual experience and the extent of bilingual exposure underlying the emergence of this early bilingual advantage. The present study addressed these two questions by assessing attentional control abilities in 7-month-old bilingual infants in comparison to same-age monolinguals and in relation to their individual bilingual exposure patterns. Findings did not reveal significant differences between monolingual and bilingual infants in the measure of attentional control and no relation between individual performance and degree of bilingual exposure. Bilinguals showed different patterns of allocating attention to the visual rewards in this task compared to monolinguals. Thus, this study indicates that bilingualism modulates attentional processes early on, possibly as a result of bilinguals' experience of encoding dual-language information from a complex linguistic input, but it does not lead to significant advantages in attentional control in the first year of life.