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The present study analyzed lexical processing efficiency in Spanish-speaking English language learners (ELLs) and their monolingual English-speaking peers from kindergarten through second grade. Specifically, changes in the patterns of speed and accuracy on a rapid object-naming task were evaluated across languages for the ELL children and across the groups of children. Repeated measures analysis of variance demonstrated that ELL children have a rapid shift in language processing efficiency from Spanish to English by the end of kindergarten. Results also showed that by the end of kindergarten ELL children were slightly faster and more accurate in English compared with their monolingual peers. This work provides perspective on how lexical processing is impacted by the development of a dual lexical system. We discuss how lexical density, strength of lexical connections, and environmental constraints may influence this rapid shift in lexical processing efficiency for young Spanish-speaking ELL children.

Background Our goal was to assess for the first time early vocalizations as precursors to speech in audio-video recordings of infants with tuberous sclerosis complex (TSC). Methods We randomly selected 40 infants with TSC from the TSC Autism Center of Excellence Research Network dataset. Using human observers, we analyzed 74 audio-video recordings within a flexible software-based coding environment. During the recordings, infants were engaged in developmental testing. We determined syllables per minute (volubility), the number of consonant-vowel combinations, such as ‘ba’ (canonical babbling), and the canonical babbling ratio (canonical syllables/total syllables) and compared the data with two groups of typically developing (TD) infants. One comparison group's data had come from a laboratory setting, while the other's had come from all-day Language Environment Analysis recordings at home. Results Compared with TD infants in laboratory and all-day Language Environment Analysis recordings, entry into the canonical babbling stage was delayed in the majority of infants with TSC, and the canonical babbling ratio was low (TD mean = 0.346, SE = 0.19; TSC mean = 0.117, SE = 0.023). Volubility level in infants with TSC was less than half that of TD infants (TD mean = 9.82, SE = 5.78; TSC mean = 3.99, SE = 2.16). Conclusions Entry into the canonical stage and other precursors of speech development were delayed in infants with TSC and may signal poor language and developmental outcomes. Future studies are planned to assess prediction of language and developmental outcomes using these measures in a larger sample and in more precisely comparable recording circumstances.

Human infant vocalization is viewed as a critical foundation for vocal learning and language. All apes share distress sounds (shrieks and cries) and laughter. Another vocal type, speech-like sounds, common in human infants, is rare but not absent in other apes. These three vocal types form a basis for especially informative cross-species comparisons. To make such comparisons possible we need empirical research documenting the frequency of occurrence of all three. The present work provides a comprehensive portrayal of these three vocal types in the human infant from longitudinal research in various circumstances of recording. Recently, the predominant vocalizations of the human infant have been shown to be speech-like sounds, or ‘protophones’, including both canonical and non-canonical babbling. The research shows that protophones outnumber cries by a factor of at least five based on data from random-sampling of all-day recordings across the first year. The present work expands on the prior reports, showing the protophones vastly outnumber both cry and laughter in both all-day and laboratory recordings in various circumstances. The data provide new evidence of the predominance of protophones in the infant vocal landscape and illuminate their role in human vocal learning and the origin of language. This article is part of the theme issue ‘Vocal learning in animals and humans’.

배경 및 목적: 음절성 옹알이의 출현은 생후 1년 동안 점진적으로 습득해가는 말산출 능력에 있어서 가장 중요한 발달을 의미한다. 본연구는 아동의 자연스런 가정 환경에서 하루 동안 수집된 발성 자료를 토대로 4-9개월 한국 아동의 음절성 옹알이의 발달을 자세히 살펴보고자 하였다. 방법: 주양육자의 보고에 따라 출생 전-중-후와 발달상의 문제가 없었던 생후...

There is a growing body of research emphasizing the role of social and endogenous motivations in human development. The present study evaluated canonical babbling across the second-half year of life using all-day recordings of 98 children with typical or elevated likelihoods of autism i.e., at “low risk” or “high risk”, respectively. Canonical babbling ratios (CBRs) were calculated from human coding along with Likert-scale ratings on vocal turn taking and vocal play in each segment. We observed no main effect of risk on CBRs. CBRs were significantly elevated during high vocal play. High turn taking yielded a weaker significant effect. We conclude that both social and endogenous motivations may drive infants’ tendencies to produce their most advanced vocal forms.

Early human infant vocalization is viewed as forming not only a critical foundation for vocal learning of language, but also a crucial realm of communication affecting emotional and social development. Although speech-like sounds are rare or absent in other ape infants, they share distress sounds (shrieks and cries) and laughter with humans, forming a potential basis for especially informative cross-species comparisons as well as potential insights regarding usage and learning of vocal sounds. A fundamental need to make such comparisons possible is empirical research to document frequency of occurrence of vocalizations of various types in natural environments.The present work focuses on laughter in the human infant, a topic that has been viewed by many as a key factor in social development for humans and other apes. Yet we know of no research quantifying frequency of occurrence of human infant laughter in natural environments across the first year. In the past two decades it has been shown that the predominant vocalizations of the human infant are “protophones”, the precursor sounds to speech. Longitudinal research has indicated unambiguously that protophones outnumber cries by a factor of at least five based on data from random-sampling of all-day recordings across the whole first year. The present work expands on the prior reports by reporting data showing that human infant laughter occurs even more rarely than cry in all-day recordings. Yet laughter is clearly a salient and important aspect of social development. We reason about the dominance of protophones in the infant vocal landscape in light of their role in illuminating human vocal learning and the origin of language.

Both vocalization and gesture are universal modes of communication and fundamental features of language development. Many believe that language evolved out of early gestural use; however, evidence reported here suggests vocalization precedes gesture in human communication and forms the predominant foundation for language. To our knowledge no prior research has investigated the rates of emergence of both gesture and vocalization in human infants to evaluate this question. We evaluated the rates of gesture and speech-like vocalizations (protophones) of 10 infants at 4, 7, and 11 months of age using parent-infant laboratory recordings. We found that infant protophones outnumbered gestures substantially at all three ages, ranging from >30 times more protophones than gestures at 3 months, to more than twice as many protophones as gestures at 11 months. The results suggest that vocalization is the predominant mode of communication in human infants from the beginning of life.

Aims and objectives:We know little about how the rate of speaking develops in bilingual children. The purpose of the current investigation was to explore the second language (L2) articulation rate in Spanish-English bilingual kindergarten children, and to compare the rates with those of monolingual English-speaking peers.Method/design:We performed a group-level, longitudinal study comparing articulation rates in two language groups (monolingual and bilingual).Data and analysis:Sixty-two monolingual English-speaking children and 62 Spanish-English bilingual peers repeated English-based nonwords of two-, three-, and four-syllable length; half contained complex syllable constructions (i.e., consonant clusters). Accuracy was treated as a measure of phonological knowledge. Articulatory duration for each nonword production was calculated, and duration measures were converted to syllables per second. English standardized vocabulary and phonological processing tests also were administered. Follow-up analyses compared a subsample of 19 Spanish-dominant children to 19 monolingual peers with relatively high language performance.Results:Bilingual children’s scores were significantly lower than those of their monolingual peers for English vocabulary, nonword repetition accuracy, and phonological processing. Despite this discrepancy, there was no statistically significant difference in the articulation rates of the two language groups either at the beginning or end of kindergarten. Nonwords with more frequent English phonological patterns were produced faster than nonwords with less frequent phonological patterns. Despite their increase in English language skills across the school year, neither language group experienced accompanying differences in articulation rate.Conclusions:These results demonstrate that Spanish-English bilingual children’s articulation rate while repeating nonwords of various length and complexity is similar to that of monolingual children’s, despite the bilingual children’s limited English phonological knowledge as measured by nonword repetition accuracy and sound matching. This runs contrary to expectations based on mainstream models that rely on frequency effects. We speculate that bilingual performance might be related to peer influences secondary to L2 immersion.

Canonical babbling (CB) is critical in forming foundations for speech. Research has shown that the emergence of CB precedes first words, predicts language outcomes, and is delayed in infants with several communicative disorders. We seek a naturalistic portrayal of CB development, using all-day home recordings to evaluate the influences of age, language, and social circumstances on infant CB production. Thus we address the nature of very early language foundations and how they can be modulated. This is the first study to evaluate possible interactions of language and social circumstance in the development of babbling. We examined the effects of age (6 and 11 months), language/culture (English and Chinese), and social circumstances (during infant-directed speech [IDS], during infant overhearing of adult-directed speech [ADS], or when infants were alone) on canonical babbling ratios (CBR = canonical syllables/total syllables). The results showed a three-way interaction of infant age by infant language/culture by social circumstance. The complexity of the results forces us to recognize that a variety of factors can interact in the development of foundations for language, and that both the infant vocal response to the language/culture environment and the language/culture environment of the infant may change across age.

Both vocalization and gesture are universal modes of communication and fundamental features of language development. The gestural origins theory proposes that language evolved out of early gestural use. However, evidence reported here suggests vocalization is much more prominent in early human communication than gesture is. To our knowledge no prior research has investigated the rates of emergence of both gesture and vocalization across the first year in human infants. We evaluated the rates of gestures and speech-like vocalizations (protophones) in 10 infants at 4, 7, and 11 months of age using parent-infant laboratory recordings. We found that infant protophones outnumbered gestures substantially at all three ages, ranging from >35 times more protophones than gestures at 3 months, to >2.5 times more protophones than gestures at 11 months. The results suggest vocalization, not gesture, is the predominant mode of communication in human infants in the first year.

Receptive standardized vocabulary scores have been found to be much higher than expressive standardized vocabulary scores in children with Spanish as L1, learning L2 (English) in school (Gibson et al., 2012). Here we present evidence suggesting the receptive-expressive gap may be harder to evaluate than previously thought. We compared the performance of 116 six-year-old Spanish–English bilingual children in the US to 30 monolingual Spanish-speaking peers in Mexico across two Spanish-language standardized picture naming tests and one standardized picture pointing test. The performance of 134 monolingual English-speaking peers was compared using similar English-language tests. Results revealed the presence and magnitude of a receptive-expressive gap was largely dependent on the tests used. These discrepant results likely exist because widely-used standardized tests do not offer comparable normed scores. We review possible test norming practices that may have contributed to these results and suggest guidelines to determine a meaningful receptive-expressive gap for bilingual children.

Research on infant vocal development has provided notable insights into vocal interaction with caregivers, elucidating growth in foundations for language through parental elicitation and reaction to vocalizations. A role for infant vocalizations produced endogenously, potentially providing raw material for interaction and a basis for growth in the vocal capacity itself, has received less attention. We report that in laboratory recordings of infants and their parents, the bulk of infant speech-like vocalizations, or “protophones”, were directed toward no one and instead appeared to be generated endogenously, mostly in exploration of vocal abilities. The tendency to predominantly produce protophones without directing them to others occurred both during periods when parents were instructed to interact with their infantsandduring periods when parents were occupied with an interviewer, with the infants in the room. The results emphasize the infant as an agent in vocal learning, even when not interacting socially and suggest an enhanced perspective on foundations for vocal language.

This study investigated reliability of naturalistic listening in real time (NLRT) compared to phonetic transcription. Speech pathology students with brief training in NLRT assessed prelinguistic syllable inventory size and specific syllable types in typically developing infants. A second study also examined inter-coder reliability for canonical babbling, canonical babbling ratio and presence of oral stops in syllable inventory of infants with cleft palate, by means of NLRT. In study 1, ten students independently assessed prelinguistic samples of five 12-month-old typically developing infants using NLRT and phonetic transcription. Coders assessed syllable inventory size as more than twice as large using phonetic transcription as NLRT. Results showed a strong correlation between NLRT and phonetic transcription (syllables with more than five occurrences) for syllable inventory size (r = .60; p In study 2, three other students assessed prelinguistic samples of twenty-eight 12-month-old infants with cleft palate by means of NLRT. Results revealed perfect inter-coder agreement for presence/absence of canonical babbling, strong correlations between the three coders’ assessment of syllable inventory size (average r = .83; p In conclusion, NLRT is a reliable method for assessing prelinguistic measures in infants with and without cleft palate with inter-coder agreement levels comparable to phonetic transcription for specific syllable types.

Temporal coordination of vocal exchanges between mothers and their infants emerges from a developmental process that relies on the ability of communication partners to co-coordinate and predict each other's turns. Consequently, the partners engage in communicative niche construction that forms a foundation for language in human infancy. While robust universals in vocal turn-taking have been found, differences in the timing of maternal and infant vocalizations have also been reported across cultures. In this study, we examine the temporal structure of vocal interactions in 38 mother-infant dyads in the first two years across two cultures-American and Lebanese-by studying observed and randomized distributions of vocalizations, focusing on both gaps and overlaps in naturalistic 10-min vocal interactions. We conducted a series of simulations using Kolmogorov-Smirnov (K-S) tests to examine whether the observed responsivity patterns differed from randomly generated simulations of responsivity patterns in both Arabic and English for mothers responding to infants and for infants responding to mothers. Results revealed that both mothers and infants engaged in conversational alternation, with mothers acting similarly across cultures. By contrast, significant differences were observed in the timing of infant responses to maternal utterances, with the Lebanese infants' tendency to cluster their responses in the first half-second after the offset of the Lebanese mothers' utterances to a greater extent than their American counterparts. We speculate that the results may be due to potential phonotactic differences between Arabic and English and/or to differing child-rearing practices across Lebanese and American cultures. The findings may have implications for early identification of developmental disorders such as autism spectrum disorders within and across cultures.

How did vocal language originate? Before trying to determine how referential vocabulary or syntax may have arisen, it is critical to explain how ancient hominins began to produce vocalization flexibly, without binding to emotions or functions. A crucial factor in the vocal communicative split of hominins from the ape background may thus have been copious, functionally flexible vocalization, starting in infancy and continuing throughout life, long before there were more advanced linguistic features such as referential vocabulary. 2–3 month-old modern human infants produce “protophones”, including at least three types of functionally flexible non-cry precursors to speech rarely reported in other ape infants. But how early in life do protophones actually appear? We report that the most common protophone types emerge abundantly as early as vocalization can be observed in infancy, in preterm infants still in neonatal intensive care. Contrary to the expectation that cries are the predominant vocalizations of infancy, our all-day recordings showed that protophones occurred far more frequently than cries in both preterm and full-term infants. Protophones were not limited to interactive circumstances, but also occurred at high rates when infants were alone, indicating an endogenous inclination to vocalize exploratorily, perhaps the most fundamental capacity underlying vocal language.

Theory and research suggest that vocal development predicts "useful speech" in preschoolers with autism spectrum disorder (ASD), but conventional methods for measurement of vocal development are costly and time consuming. This longitudinal correlational study examines the reliability and validity of several automated indices of vocalization development relative to an index derived from human coded, conventional communication samples in a sample of preverbal preschoolers with ASD. Automated indices of vocal development were derived using software that is presently "in development" and/or only available for research purposes and using commercially available Language ENvironment Analysis (LENA) software. Indices of vocal development that could be derived using the software available for research purposes: (a) were highly stable with a single day-long audio recording, (b) predicted future spoken vocabulary to a degree that was nonsignificantly different from the index derived from conventional communication samples, and (c) continued to predict future spoken vocabulary even after controlling for concurrent vocabulary in our sample. The score derived from standard LENA software was similarly stable, but was not significantly correlated with future spoken vocabulary. Findings suggest that automated vocal analysis is a valid and reliable alternative to time intensive and expensive conventional communication samples for measurement of vocal development of preverbal preschoolers with ASD in research and clinical practice. Autism Res 2017, 10: 508-519. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Prior research on ambient-language effects in babbling has often suggested infants produce language-specific phonological features within the first year. These results have been questioned in research failing to find such effects and challenging the positive findings on methodological grounds. We studied English- and Chinese-learning infants at 8, 10, and 12 months and found listeners could not detect ambient-language effects in the vast majority of infant utterances, but only in items deemed to be words or to contain canonical syllables that may have made them sound like words with language-specific shapes. Thus, the present research suggests the earliest ambient-language effects may be found in emerging lexical items or in utterances influenced by language-specific features of lexical items. Even the ambient-language effects for infant canonical syllables and words were very small compared with ambient-language effects for meaningless but phonotactically well-formed syllable sequences spoken by adult native speakers of English and Chinese.

Objectives This study investigated automatic assessment of vocal development in children with hearing loss compared with children who are typically developing, have language delays, and have autism spectrum disorder. Statistical models are examined for performance in a classification model and to predict age within the four groups of children. Design The vocal analysis system analyzed 1913 whole-day, naturalistic acoustic recordings from 273 toddlers and preschoolers comprising children who were typically developing, hard of hearing, language delayed, or autistic. Results Samples from children who were hard of hearing patterned more similarly to those of typically developing children than to the language delayed or autistic samples. The statistical models were able to classify children from the four groups examined and estimate developmental age based on automated vocal analysis. Conclusions This work shows a broad similarity between children with hearing loss and typically developing children, although children with hearing loss show some delay in their production of speech. Automatic acoustic analysis can now be used to quantitatively compare vocal development in children with and without speech-related disorders. The work may serve to better distinguish among various developmental disorders and ultimately contribute to improved intervention.

In this article, the author discusses social feedback loops and cascading effects in Autism spectrum disorder, and also mentions motor ability and communicative motivation of Autism.

Seeking roots of language, we probed infant facial expressions and vocalizations. Both have roles in language, but the voice plays an especially flexible role, expressing a variety of functions and affect conditions with the same vocal categories—a word can be produced with many different affective flavors. This requirement of language is seen in very early infant vocalizations. We examined the extent to which affect is transmitted by early vocal categories termed “protophones” (squeals, vowel-like sounds, and growls) and by their co-occurring facial expressions, and similarly the extent to which vocal type is transmitted by the voice and co-occurring facial expressions. Our coder agreement data suggests infant affect during protophones was most reliably transmitted by the face (judged in video-only), while vocal type was transmitted most reliably by the voice (judged in audio-only). Voice alone transmitted negative affect more reliably than neutral or positive affect, suggesting infant protophones may be used especially to call for attention when the infant is in distress. By contrast, the face alone provided no significant information about protophone categories. Indeed coders in video-only could scarcely recognize the difference between silence and voice when coding protophones in video-only. The results suggest that partial decoupling of communicative roles for face and voice occurs even in the first months of life. Affect in infancy appears to be transmitted in a way that audio and video aspects are flexibly interwoven, as in mature language.

An infant’s vocal capacity develops significantly during the first year of life. Research suggests early measures of pre-speech development, such as canonical babbling and volubility, can differentiate typical versus disordered development. This study offers a new contribution by comparing early vocal development in 10 infants with Fragile X syndrome and 14 with typical development. Results suggest infants with Fragile X syndrome produce fewer syllables and have significantly lower canonical babbling ratios (i.e., canonical syllables/total syllables) compared to infants who are typically developing. Furthermore, the particular measures of babbling were strong predictors of group membership, adding evidence regarding the possible utility of these markers in early identification.

Functional flexibility, as manifest in the use of any word or sentence to express different affective valences on different occasions, is required in linguistic communication and can be said to be an infrastructural property of language. Early infant vocalizations (protophones), believed to be precursors to speech, occur in the first month and are functionally different from non-speech-like signals (i.e., cries and laughs). Oller et al. (2013) showed that infants by three months used three different protophone types with a full range of affect as manifest in facial expression, from positive to neutral to negative. These differences in affect were also shown to correspond to different illocutionary functions, unlike fixed signals or vegetative sounds, which showed functional rigidity. The present study investigated whether infants show functional flexibility in protophones even earlier than the ages studied by Oller et al (2013). Data were obtained from 6 infants across the first three months. Results showed that as early as the first month, infant protophones were already accompanied by variable facial affect valences and continued to be affectively flexible at the later ages. The present study thus documents the very early emergence of an infrastructural property of human communication.

Summary The primary vocal registers of modal, falsetto, and fry have been studied in adults but not per se in infancy. The vocal ligament is thought to play a critical role in the modal-falsetto contrast but is still developing during infancy (Tateya and Tateya, 2015). 41 Cover tissues are also implicated in the modal-fry contrast, but the low fundamental frequency ( f o ) cutoff of 70 Hz, shared between genders, suggests a psychoacoustic basis for the contrast. Buder, Chorna, Oller, and Robinson (2008) 6 used the labels of “loft,” “modal,” and “pulse” for distinct vibratory regimes that appear to be identifiable based on spectrographic inspection of harmonic structure and auditory judgments in infants, but this work did not supply acoustic measurements to verify which of these nominally labeled regimes resembled adult registers. In this report, we identify clear transitions between registers within infant vocalizations and measure these registers and their transitions for f o and relative harmonic amplitudes (H1-H2). By selectively sampling first-year vocalizations, this manuscript quantifies acoustic patterns that correspond to vocal fold vibration types not previously cataloged in infancy. Results support a developmental basis for vocal registers, revealing that a well-developed ligament is not needed for loft-modal quality shifts as seen in harmonic amplitude measures. Results also reveal that a distinctively pulsatile register can occur in infants at a much higher f o than expected on psychoacoustic grounds. Overall results are consistent with cover tissues in infancy that are, for vibratory purposes, highly compliant and readily detached.

Canonical babbling is a critical milestone for speech development and is usually well in place by 10 months. The possibility that infants with autism spectrum disorder (ASD) show late onset of canonical babbling has so far eluded evaluation. Rate of vocalization or "volubility" has also been suggested as possibly aberrant in infants with ASD. We conducted a retrospective video study examining vocalizations of 37 infants at 9-12 and 15-18 months. Twenty-three of the 37 infants were later diagnosed with ASD and indeed produced low rates of canonical babbling and low volubility by comparison with the 14 typically developing infants. The study thus supports suggestions that very early vocal patterns may prove to be a useful component of early screening and diagnosis of ASD.

The study of vocal coordination between infants and adults has led to important insights into the development of social, cognitive, emotional, and linguistic abilities. We used an automatic system to identify vocalizations produced by infants and adults over the course of the day for fifteen infants studied longitudinally during the first 2 years of life. We measured three different types of vocal coordination: coincidence-based, rate-based, and cluster-based. Coincidence-based coordination and rate-based coordination are established measures in the developmental literature. Cluster-based coordination is new and measures the strength of matching in the degree to which vocalization events occur in hierarchically nested clusters. We investigated whether various coordination patterns differ as a function of vocalization type, whether different coordination patterns provide unique information about the dynamics of vocal interaction, and how the various coordination patterns each relate to infant age. All vocal coordination patterns displayed greater coordination for infant speech-related vocalizations, adults adapted the hierarchical clustering of their vocalizations to match that of infants, and each of the three coordination patterns had unique associations with infant age. Altogether, our results indicate that vocal coordination between infants and adults is multifaceted, suggesting a complex relationship between vocal coordination and the development of vocal communication.

Lay Abstract Measuring the degree to which young children’s vocalizations, many of which are non-words, have acoustic characteristics similar to speech may eventually help us match expectations and treatment methods to individual needs and abilities. To accomplish this goal, we need vocal measures that have scientific utility. The current study indicates that a single all-day recording and subsequent computer-analysis of its acoustic characteristics produces a measure of vocal development that is highly related to expressive language in children with ASD and in children who are typically developing. These findings provide the needed basis for future use of this measure for clinical and scientific purposes.

Purpose The prelinguistic infant’s babbling repertoire of syllables —the phonological categories that form the basis for early word learning—is noticed by caregivers who interact with infants around them. Prior research on babbling has not explored the caregiver’s role in recognition of early vocal categories as foundations for word learning. In the present work, the authors begin to address this gap. Method The authors explored vocalizations produced by 8 infants at 3 ages (8, 10, and 12 months) in studies illustrating identification of phonological categories through caregiver report, laboratory procedures simulating the caregiver’s natural mode of listening, and the more traditional laboratory approach (phonetic transcription). Results Caregivers reported small repertoires of syllables for their infants. Repertoires of similar size and phonetic content were discerned in the laboratory by judges who simulated the caregiver’s natural mode of listening. However, phonetic transcription with repeated listening to infant recordings yielded repertoire sizes that vastly exceeded those reported by caregivers and naturalistic listeners. Conclusions The results suggest that caregiver report and naturalistic listening by laboratory staff can provide a new way to explore key characteristics of early infant vocal categories, a way that may provide insight into later speech and language development. Supplemental Material https://doi.org/10.23641/asha.6170384

This is a commentary on the article (this issue) by Giulivi, Whalen, Goldstein, Nam, and Levitt (GW) and on the Frames, then Content (FC) theory that the article critiques. The commentary agrees with GW that the FC theory has not been adequately supported by data to show a developmental pattern of reduction in “frame dominance” across human infancy. The commentary elaborates on another apparent problem highlighted by GW, that is, while expected-to-observed ratios of syllable types appear to support FC theory, raw frequency data (at least the ones from GW) seem to contradict it. The commentary also argues that phonetic transcription, the primary method of the FC model and the critique by GW, has limited reliability and validity and should not be utilized in early vocal development research without additional methods for interpretive guidance. Another weakness of the FC theory, as formulated, is that it offers no useful way to portray precanonical vocal development, which appears to be critical to subsequen...

Purpose To develop a system for numerically quantifying a speaker’s phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, the authors describe a system for differentially weighting speech sound errors on the basis of various levels of phonetic accuracy using a Weighted Speech Sound Accuracy (WSSA) score. The authors then evaluate the reliability and validity of this measure. Method Phonetic transcriptions were analyzed from several samples of child speech, including preschoolers and young adolescents with and without speech sound disorders and typically developing toddlers. The new measure of phonetic accuracy was validated against existing measures, was used to discriminate typical and disordered speech production, and was evaluated to examine sensitivity to changes in phonetic accuracy over time. Reliability between transcribers and consistency of scores among different word sets and testing points are compared. Results Initial psychometric data indicate that WSSA scores correlate with other measures of phonetic accuracy as well as listeners' judgments of the severity of a child’s speech disorder. The measure separates children with and without speech sound disorders and captures growth in phonetic accuracy in toddlers' speech over time. The measure correlates highly across transcribers, word lists, and testing points. Conclusion Results provide preliminary support for the WSSA as a valid and reliable measure of phonetic accuracy in children’s speech.

Major innovations are becoming available for research in language development and disorders. Among these innovations, recent tools allow naturalistic recording in children’s homes and automated analysis to facilitate representative sampling. This study employed all-day recordings during the 2nd year of life in a child exposed to three languages, using a fully wearable battery-powered recorder, with automated analysis to locate appropriate time periods for coding. This method made representative sampling possible and afforded the opportunity for a case study indicating that language spoken directly to the child had dramatically more effect on vocabulary learning than audible language not spoken to the child, as indicated by chi-square analyses of the child’s verbal output and input in each of the languages. The work provides perspective on the role of learning words by overhearing in childhood and suggests the value of representative naturalistic sampling as a means of research on vocabulary acquisition.

The study compared the vocal production and language learning environments of 26 young children with autism spectrum disorder (ASD) to 78 typically developing children using measures derived from automated vocal analysis. A digital language processor and audio-processing algorithms measured the amount of adult words to children and the amount of vocalizations they produced during 12-h recording periods in their natural environments. The results indicated significant differences between typically developing children and children with ASD in the characteristics of conversations, the number of conversational turns, and in child vocalizations that correlated with parent measures of various child characteristics. Automated measurement of the language learning environment of young children with ASD reveals important differences from the environments experienced by typically developing children.

Delays in the onset of canonical babbling with hearing loss are extensively documented. Relatively little is known about other aspects of prelinguistic vocal development and hearing loss. Eight infants with typical hearing and eight with severe-to-profound hearing loss were matched with regard to a significant vocal development milestone, the onset of canonical babbling, and were examined at three points in time: before, at, and after the onset of canonical babbling. No differences in volubility were noted between the two infant groups. Growth in canonical babbling appeared to be slower for infants with hearing loss than infants with typical hearing. Glottal and glide production was similar in both groups. The results add to a body of information delineating aspects of prelinguistic vocal development that seem to differ or to be similar in infants with hearing loss compared to infants with typical hearing.

Summary Infant phonation is highly variable in many respects, including the basic vibratory patterns by which the vocal tissues create acoustic signals. Previous studies have identified the regular occurrence of nonmodal phonation types in normal infant phonation. The glottis is like many oscillating systems that, because of nonlinear relationships among the elements, may vibrate in ways representing the deterministic patterns classified theoretically within the mathematical framework of nonlinear dynamics. The infant's preverbal vocal explorations present such a variety of phonations that it may be possible to find effectively all the classes of vibration predicted by nonlinear dynamic theory. The current report defines acoustic criteria for an important subset of such vibratory regimes, and demonstrates that analysts can be trained to reliably use these criteria for a classification that includes all instances of infant phonation in the recorded corpora. The method is thus internally comprehensive in the sense that all phonations are classified, but it is not exhaustive in the sense that all vocal qualities are thereby represented. Using the methods thus developed, this study also demonstrates that the distributions of these phonation types vary significantly across sessions of recording in the first year of life, suggesting developmental changes. The method of regime classification is thus capable of tracking changes that may be indicative of maturation of the mechanism, the learning of categories of phonatory control, and the possibly varying use of vocalizations across social contexts.

Little research has been conducted on the development of suprasegmental characteristics of vocalizations in typically developing infants (TDI) and the role of audition in the development of these characteristics. The purpose of the present study was to examine the longitudinal development of fundamental frequency (F(0)) in eight TDI and eight infants with severe-to-profound hearing loss matched for level of vocal development. Results revealed no significant changes in F(0) with advances in pre-language vocal development for TDI. Infants with hearing loss, however, showed a statistically reliable higher variability of F(0) than TDI, when age was accounted for as a covariate. The results suggest development of F(0) may be strongly influenced by audition.

Although parental volubility, or amount of talk, has received considerable recent attention, infant volubility has received comparatively little attention despite its potential significance for communicative risk status and later linguistic and cognitive outcomes. Volubility of 16 typically developing infants from 2 to 11 months of age was longitudinally investigated in the present study across three social circumstances: parent talking to infant, parent not talking to infant and parent talking to interviewer while the infant was in the room. Results indicated that volubility was least in the Interview circumstance. There were no significant differences in volubility between the parent Talk and No Talk circumstances. Volubility was found to reduce with age. These results suggest that infants vocalise in a variety of circumstances, even when no one talks to or interacts with them. The presence of a stranger or perhaps overhearing adults speaking to each other, however, may significantly reduce infant volubility.

Purpose Onset of canonical babbling by 10 months of age is surprisingly robust in infancy, suggesting that there must be deep biological forces that keep the development of this key vocal capability on course. This study further evaluated the robustness of canonical babbling and other aspects of prelinguistic vocal development. Method Longitudinal observation was conducted on 4 infants who were at risk for abnormal vocal development because of bilateral moderate-to-severe sensorineural hearing loss and additional risk factors for developmental delay. Results Two of the infants were delayed in the onset of canonical babbling and showed greater fluctuation in canonical babbling ratios following its onset than did typically developing infants. On the same measures, the remaining 2 infants were within normal limits, although their age of onset for canonical babbling was later than the mean for typically developing infants. Volubility was not notably different from typically developing infants. Differences from typically developing infants were, however, observed in proportions of various prelinguistic syllable types produced across time. Conclusion Results provided further evidence of robustness of canonical babbling and indicated the need for a large parametric study evaluating effects of varying degrees of hearing loss and other risk factors on vocal development.

The purpose of this study is to provide new perspectives on correlates of phonetic transcription agreement. Our research focuses on phonetic transcription and coding of infant vocalizations. The findings are presumed to be broadly applicable to other difficult cases of transcription, such as found in severe disorders of speech, which similarly result in low reliability for a variety of reasons. We evaluated the predictiveness of two factors not previously documented in the literature as influencing transcription agreement: canonicity and coder confidence. Transcribers coded samples of infant vocalizations, judging both canonicity and confidence. Correlation results showed that canonicity and confidence were strongly related to agreement levels, and regression results showed that canonicity and confidence both contributed significantly to explanation of variance. Specifically, the results suggest that canonicity plays a major role in transcription agreement when utterances involve supraglottal articulation, with coder confidence offering additional power in predicting transcription agreement.

We analyzed the microstructure of child-adult interaction during naturalistic, daylong, automatically labeled audio recordings (13,836 hr total) of children (8- to 48-month-olds) with and without autism. We found that an adult was more likely to respond when the child’s vocalization was speech related rather than not speech related. In turn, a child’s vocalization was more likely to be speech related if the child’s previous speech-related vocalization had received an immediate adult response rather than no response. Taken together, these results are consistent with the idea that there is a social feedback loop between child and caregiver that promotes speech development. Although this feedback loop applies in both typical development and autism, children with autism produced proportionally fewer speech-related vocalizations, and the responses they received were less contingent on whether their vocalizations were speech related. We argue that such differences will diminish the strength of the social feedback loop and have cascading effects on speech development over time. Differences related to socioeconomic status are also reported.

The growing field of evo-devo is increasingly demonstrating the complexity of steps involved in genetic, intracellular regulatory, and extracellular environmental control of the development of phenotypes. A key result of such work is an account for the remarkable plasticity of organismal form in many species based on relatively minor changes in regulation of highly conserved genes and genetic processes. Accounting for behavioral plasticity is of similar potential interest but has received far less attention. Of particular interest is plasticity in communication systems, where human language represents an ultimate target for research. The present paper considers plasticity of language capabilities in a comparative framework, focusing attention on examples of a remarkable fact: Whereas there exist design features of mature human language that have never been observed to occur in non-humans in the wild, many of these features can be developed to notable extents when non-humans are enculturated through human training (especially with intensive social interaction). These examples of enculturated developmental plasticity across extremely diverse taxa suggest, consistent with the evo-devo theme of highly conserved processes in evolution, that human language is founded in part on cognitive capabilities that are indeed ancient and that even modern humans show self-organized emergence of many language capabilities in the context of rich enculturation, built on the special social/ecological history of the hominin line. Human culture can thus be seen as a regulatory system encouraging language development in the context of a cognitive background with many highly conserved features.

Modeling of evolution and development of language has principally utilized mature units of spoken language, phonemes and words, as both targets and inputs. This approach cannot address the earliest phases of development because young infants are unable to produce such language features. We argue that units of early vocal development-protophones and their primitive illocutionary/perlocutionary forces-should be targeted in evolutionary modeling because they suggest likely units of hominin vocalization/communication shortly after the split from the chimpanzee/bonobo lineage, and because early development of spontaneous vocal capability is a logically necessary step toward vocal language, a root capability without which other crucial steps toward vocal language capability are impossible. Modeling of language evolution/development must account for dynamic change in early communicative units of form/function across time. We argue for interactive contributions of sender/infants and receiver/caregivers in a feedback loop involving both development and evolution and propose to begin computational modeling at the hominin break from the primate communicative background.

Infant vocal behaviors are extremely complex. Consequently, coding these behaviors is difficult and is typically associated with low reliability across observers. Various difficulties that arise when dealing with prelinguistic vocalizations, especially in the first 6 months of life, are outlined here. A proposed database of digitized infant vocalizations that illustrates strategies used to deal with these difficulties is then described. These strategies are based on theoretical infraphonological constructs, empirical observations, and information about the nature of mature phonological systems. Furthermore, the strategies are open-ended and can be modified as new information becomes available regarding infant vocal behaviors. At present, a preliminary database is available on the Web that illustrates some of these strategies. As the database is expanded, it is expected to provide a general framework for observers to categorize infant vocalizations and thereby enhance observer reliability.