Suzanne Curtin

PRIMIR: A Developmental Framework of Infant Speech Processing

Over the past few years, there has been an increasing emphasis on studying the link between infant speech perception and later language acquisition. This research has yielded some seemingly contradictory findings: In some studies infants appear to use phonetic and indexical detail that they fail to use in other studies. In this article we present a new, unified framework for accounting for these divergent findings. PRIMIR (a developmental framework for Processing Rich Information from Multidimensional Interactive Representations) assumes there is rich information available in the speech input and that the child picks up and organizes this information along a number of multidimensional interactive planes. Use of this rich information depends on the joint activity of 3 dynamic filters. These filters-the initial biases, the developmental level of the child, and requirements of the specific language task the child is facing-work together to differentially direct attention to 1 (or more) plane. In this article we outline the contradictory data that need to be explained, elucidate PRIMIR, including its underlying assumptions and overall architecture, and compare it to existing frameworks. We conclude by presenting core predictions of PRIMIR.

Bilingual beginnings as a lens for theory development: PRIMIR in focus

PRIMIR (Processing Rich Information from Multidimensional Interactive Representations; Curtin & Werker, 2007; Werker & Curtin, 2005) is a framework that encompasses the bidirectional relations between infant speech perception and the emergence of the lexicon. Here, we expand its mandate by considering infants growing up bilingual. We argue that, just like monolinguals, bilingual infants have access to rich information in the speech stream and by the end of their first year, they establish not only language-specific phonetic category representations, but also encode and represent both sub-phonetic and indexical detail. Perceptual biases, developmental level, and task demands work together to influence the level of detail used in any particular situation. In considering bilingual acquisition, we more fully elucidate what is meant by task demands, now understood both in terms of external demands imposed by the language situation, and internal demands imposed by the infant (e.g. different approaches to the same apparent task taken by infants from different backgrounds). In addition to the statistical learning mechanism previously described in PRIMIR, the necessity of a comparison–contrast mechanism is discussed. This refocusing of PRIMIR in the light of bilinguals more fully explicates the relationship between speech perception and word learning in all infants.

Parallels between the reading and spelling deficits of two subgroups of developmental dyslexics

The spelling errors of third graders who fit phonological andsurface profiles of developmental dyslexia were analyzed, alongwith the errors of younger (reading level matched) andchronologically age matched non-dyslexic comparison groups. InStudy 1, errors were analyzed as phonologically constrained,unconstrained, or inaccurate and as either orthographicallyacceptable or unacceptable. Study 2 extended the errorclassification system to nonword spellings. The main finding wasthat different types of dyslexics produced different types oferrors. Both studies found that children produced spelling errorsconsistent with their type of dyslexia. The phonological groupshowed poor knowledge of phoneme-grapheme correspondences,consistent with the existence of a phonological deficit. Thesurface groups spelling error profile differed from thephonological group and closely resembled the younger normalcomparison group. This pattern is consistent with other evidencethat surface dyslexia represents a general delay in acquiringliteracy skills. The studies provide converging evidence, from aspelling task, that developmental dyslexia is a non-homogeneouscategory consisting of at least two major subtypes with distinctetiologies and behavioral sequelae.

Phonological transfer and levels of representation: The perceptual acquisition of Thai voice and aspiration by English and French speakers *

In this article, we show that the generative phonological distinction between lexical and surface representation can explain apparently contradictory orders of acquisition of L2 voice and aspiration contrasts by native speakers of English. Cross-language speech perception research has shown that English speakers distinguish synthetic voice onset time counterparts of aspirated–unaspirated minimal pairs more readily than voiced–voiceless. Here, we present evidence that in the perceptual acquisition of the same Thai contrasts, English speakers acquire voicing before aspiration. These divergent orders are argued to be due to the levels of representation tapped by the methodologies employed in each case: surface representations in the earlier studies, and lexical in the present one. The resulting difference in outcomes is attributed to the presence of aspiration in surface, but not lexical, representations in English (Chomsky and Halle, 1968). To address the further question of whether allophonic aspiration in English aids in the eventual acquisition of contrastive aspiration in Thai, we compare the developmental progression of the English learners to that of native speakers of French, whose L1 contains only a voicing contrast, and no surface aspiration. The performance of the anglophone group improves over time, suggesting that L1 surface features can be lexicalized in L2 acquisition,even though they are not initially transferred across levels.

12-Month-Olds’ Phonotactic Knowledge Guides Their Word–Object Mappings

This study examined whether 12-month-olds will accept words that differ phonologically and phonetically from their native language as object labels in an associative learning task. Sixty infants were presented with sets of English word-object (N = 30), Japanese word-object (N = 15), or Czech word-object (N = 15) pairings until they habituated. Infants associated CVCV English, CCVC English, and CVCV Japanese words, but not CCVC Czech words, with novel objects. These results demonstrate that by 12 months of age, infants are beginning to apply their language-specific knowledge to their acceptance of word forms. That is, they will not map words that violate the phonotactics of their native language to objects.

Twelve-month-olds learn novel word-object pairings differing only in stress pattern*

Infants at 1 ; 2 demonstrate difficulty in accessing subtle phonetic information about newly learned word-object pairings (Stager & Werker, 1997). In this study, we examined whether or not infants can access subtle prosodic information such as lexical stress in a word learning task. We tested infants younger than 1 ; 2 to see if they could learn two new word-object associations that differ only in stress pattern (Sww versus wSw). Our results are the first to demonstrate that, even without contextual support, infants at 1 ; 0 succeed at this task, suggesting that the salient acoustic properties associated with lexical stress facilitate word-object associative learning.

Non-ASD outcomes at 36 months in siblings at familial risk for autism spectrum disorder (ASD): A baby siblings research consortium (BSRC) study

We characterized developmental outcomes of a large sample of siblings at familial high‐risk of autism spectrum disorder (ASD), who themselves did not have ASD (n = 859), and low‐risk controls with no family history of ASD (n = 473). We report outcomes at age 3 years using the Mullen Scales of Early Learning, the Autism Diagnostic Observation Schedule (ADOS), the Autism Diagnostic Interview—Revised (ADI‐R) and adaptive functioning on the Vineland Adaptive Behavior Scales. Around 11% of high‐risk siblings had mild‐to‐moderate levels of developmental delay, a rate higher than the low‐risk controls. The groups did not differ in the proportion of toddlers with mild‐to‐moderate language delay. Thirty percent of high‐risk siblings had elevated scores on the ADOS, double the rate seen in the low‐risk controls. High‐risk siblings also had higher parent reported levels of ASD symptoms on the ADI‐R and lower adaptive functioning on the Vineland. Males were more likely to show higher levels of ASD symptoms and lower levels of developmental ability and adaptive behavior than females across most measures but not mild‐to‐moderate language delay. Lower maternal education was associated with lower developmental and adaptive behavior outcomes. These findings are evidence for early emerging characteristics related to the “broader autism phenotype” (BAP) previously described in older family members of individuals with ASD. There is a need for ongoing clinical monitoring of high‐risk siblings who do not have an ASD by age 3 years, as well as continued follow‐up into school age to determine their developmental and behavioral outcomes. Autism Res 2017, 10: 169–178.

Non-ASD outcomes at 36 months in siblings at familial risk for autism spectrum disorder (ASD)

We characterized developmental outcomes of a large sample of siblings at familial high‐risk of autism spectrum disorder (ASD), who themselves did not have ASD (n = 859), and low‐risk controls with no family history of ASD (n = 473). We report outcomes at age 3 years using the Mullen Scales of Early Learning, the Autism Diagnostic Observation Schedule (ADOS), the Autism Diagnostic Interview—Revised (ADI‐R) and adaptive functioning on the Vineland Adaptive Behavior Scales. Around 11% of high‐risk siblings had mild‐to‐moderate levels of developmental delay, a rate higher than the low‐risk controls. The groups did not differ in the proportion of toddlers with mild‐to‐moderate language delay. Thirty percent of high‐risk siblings had elevated scores on the ADOS, double the rate seen in the low‐risk controls. High‐risk siblings also had higher parent reported levels of ASD symptoms on the ADI‐R and lower adaptive functioning on the Vineland. Males were more likely to show higher levels of ASD symptoms and lower levels of developmental ability and adaptive behavior than females across most measures but not mild‐to‐moderate language delay. Lower maternal education was associated with lower developmental and adaptive behavior outcomes. These findings are evidence for early emerging characteristics related to the “broader autism phenotype” (BAP) previously described in older family members of individuals with ASD. There is a need for ongoing clinical monitoring of high‐risk siblings who do not have an ASD by age 3 years, as well as continued follow‐up into school age to determine their developmental and behavioral outcomes. Autism Res 2017, 10: 169–178.

Attention to lexical stress and early vocabulary growth in 5-month-olds at risk for autism spectrum disorder

Typically developing infants differentiate strong-weak (trochaic) and weak-strong (iambic) stress patterns by 2months of age. The ability to discriminate rhythmical patterns, such as lexical stress, has been argued to facilitate language development, suggesting that a difficulty in discriminating stress might affect early word learning as reflected in vocabulary size. Children with autism spectrum disorder (ASD) often have difficulty in correctly producing lexical stress, yet little is known about how they perceive it. The current study tested 5-month-old infants with typically developing older siblings (SIBS-TD) and infants with an older sibling diagnosed with ASD (SIBS-A) on their ability to differentiate the trochaic and iambic stress patterns of the word form gaba. SIBS-TD infants showed an increased interest in attention to the trochaic stress pattern, which was also positively correlated with vocabulary comprehension at 12months of age. In contrast, SIBS-A infants attended equally to these stress patterns, although this was unrelated to later vocabulary size.

Understanding the developing sound system: interactions between sounds and words

UNLABELLED Over the course of the first 2 years of life, infants are learning a great deal about the sound system of their native language. Acquiring the sound system requires the infant to learn about sounds and their distributions, sound combinations, and prosodic information, such as syllables, rhythm, and stress. These aspects of the phonological system are being learned simultaneously as the infant experiences the language around him or her. What binds all of the phonological units is the context in which they occur, namely, words. In this review, we explore the development of phonetics and phonology by showcasing the interactive nature of the developing lexicon and sound system with a focus on perception. We first review seminal research in the foundations of phonological development. We then discuss early word recognition and learning followed by a discussion of phonological and lexical representations. We conclude by discussing the interactive nature of lexical and phonological representations and highlight some further directions for exploring the developing sound system. WIREs Cogn Sci 2014, 5:589-602. doi: 10.1002/wcs.1307 For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.