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Phonological models of early word learning often assume that child forms can be understood as structural mappings from their adult targets. In contrast, the whole-word phonology model suggests that on beginning word production children represent adult targets as holistic units, reflecting not the exact sound sequence but only the most perceptually salient elements or those that align with their own vocal patterns. Here we ask whether the predictions of the whole-word model are supported by data from children learning Japanese or Mandarin, both languages with phonotactic structures differing from any so far investigated from this perspective. The Japanese child word forms are found to include some characteristics suggestive of whole-word representation, but in Mandarin we find little or no such evidence. Instead, some children are found to make idiosyncratic use of whole syllables, substituting them for target syllables that they match in neither onset nor rime. This result, which neither model anticipates, forces reconsideration of a key tenet of the whole-word model–that early word production is based on word-size holistic representations; instead, at least in some languages, the syllable may serve as the basic representational unit for child learners.

It has been shown that infants can increase or modify a motorically available behavior such as sucking, kicking, arm waving, etc., in response to a positive visual reinforcement (e.g., DeCasper & Fifer, 1980; Millar, 1990; Rochat & Striano, 1999; Rovee-Collier, 1997; Watson & Ramey, 1972). We tested infants to determine if they would also change their vocal behavior in response to contingent feedback, which lacks the social, emotional, and auditory modeling typical of parent-child interaction. Here, we show that in a single five-minute session infants increase the rate of their vocalizations in order to control the appearance of colorful shapes on an iPad screen. This is the first experimental study to demonstrate that infants can rapidly learn to increase their vocalizations, when given positive reinforcement with no social element. This work sets the foundations for future studies into the causal relationship between the number of early vocalizations and the onset of words. In addition, there are potential clinical applications for reinforcing vocal practice in infant populations who are at risk for poor language skills.

This systematic review surveys research on the associations between sleep and the memory processes involved in word learning in infancy. Only 16 studies were found to address this topic directly, identifying associations between infant sleep, the identification of word forms in running speech and the stabilisation and generalisation of new word form-meaning associations. Some studies investigated changes in brain responses after word learning and in sleep parameters during post-learning sleep. Others investigated the long-term effects of sleeping patterns on later vocabulary development. All but one of these studies identified positive associations between sleep and word learning in early childhood, extending similar findings in adults and school-aged children. However, there remain several gaps in the current research on early lexical development and sleep; future investigations should address these gaps to better understand lexical development and to create links between memory and language acquisition research.

The peculiar sound structure of Danish has been argued to reduce the salience of cues that allow infants to extract information from the speech stream. To assess whether caregivers adjust their infant-directed speech (IDS) to accommodate these processing challenges, this study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers’ spontaneous speech addressed to their 11-24-month-old infants and an adult experimenter. The data were collected between 2016-2018 in Aarhus, Denmark. Prosodic properties of Danish IDS conformed to cross-linguistic patterns, with a higher pitch, greater pitch variability and slower articulation rate than ADS. Crucially, though, vocalic properties contradicted cross-linguistic tendencies: Danish IDS was produced with a reduced or similar vowel space, higher within-vowel variability, and lower degree of vowel discriminability than ADS.

When speaking to infants, adults often produce speech that differs systematically from that directed to other adults. In order to quantify the acoustic implementation of this speech style across a wide variety of languages and cultures, we extracted results from empirical studies on the acoustic features of infant-directed speech (IDS). We analyzed data from 87 unique studies (669 effect sizes) on the following five acoustic parameters that have been systematically examined in the literature: i) fundamental frequency (fo), ii) fo variability, iii) vowel space area, iv) articulation rate, and v) vowel duration. Moderator analyses were conducted in hierarchical Bayesian robust regression models in order to examine how these features change with infant age and differ across languages, experimental tasks and recording environments. The moderator analyses indicated that fo, articulation rate, and vowel duration became more similar to adult-directed speech (ADS) over time, whereas fo variability and vowel space area exhibited stability throughout development. These results point the way for future research to disentangle different accounts of the functions and learnability of IDS by conducting theory-driven comparisons among different languages and using computational models to formulate testable predictions.

This paper quantifies the extent to which infants can perceive audio-visual congruence for speech information and assesses whether this ability changes with native-language exposure over time. A hierarchical Bayesian robust regression model of 92 separate effect sizes extracted from 24 studies indicates a moderate effect size in a positive direction (0.35, CI [0.21: 0.50]). This result suggests that infants possess a robust ability to detect audio-visual congruence for speech. Moderator analyses, moreover, suggest that infants’ audio-visual matching ability for speech emerges at an early point in the process of language acquisition and remains stable for both native and non-native speech throughout early development. A sensitivity analysis of the meta-analytic data, however, indicates that a moderate publication bias for significant results could shift the lower credible interval to include null effects. Based on these findings, we outline recommendations for new lines of enquiry and suggest ways to improve the replicability of results in future investigations.

Bayesian accounts of development posit that infants form predictions about the causes of sensory signals in their environment and select actions that resolve the largest amount of uncertainty. This paper considers how this approach to infant development can inform and unify insights from experimental research on early cognitive development and language acquisition. In order to establish whether infants’ early inferential abilities conform to the basic assumptions of a Bayesian approach to cognition, we first conduct a systematic review of experimental studies on infants’ ability to form predictions about probabilistic contingencies. These studies provide evidence that infants exhibit sensitivity to the probabilistic structure of their surrounding environment and recruit their own uncertainty to guide their exploration of information in the world. We then demonstrate how these Bayesian computational principles may apply in the context of language acquisition by conducting a second systematic review of experiments on the facilitative role of infants’ vocal production. These studies indicate that infants are more likely to produce and allocate attention to those speech sounds that best afford the opportunity to reduce prediction error over time. This paper demonstrates how Bayesian models of cognition can offer a unifying framework to advance the understanding of cognitive processes in early development. This framework not only gives a larger perspective to current findings, but also provides conceptual tools to enable investigation of infants’ individual trajectories of behavioural change.

This project set out to develop an app for infants under one year of age that responds in real time to language-like infant utterances with attractive images on an iPad screen. Language-like vocalisations were defined as voiced utterances which were not high pitched squeals, nor shouts. The app, BabblePlay, was intended for use in psycholinguistic research to investigate the possible causal relationship between early canonical babble and early onset of word production. It is also designed for a clinical setting, (1) to illustrate the importance of feedback as a way to encourage infant vocalisations, and (2) to provide consonant production practice for infant populations that do not vocalise enough or who vocalise in an atypical way, specifically, autistic infants (once they have begun to produce consonants). This paper describes the development and testing of BabblePlay, which responds to an infant’s vocalisations with colourful moving shapes on the screen that are analogous to some features of the infant’s vocalization including loudness and duration. Validation testing showed high correlation between the app and two human judges in identifying vocalisations in 200 min of BabblePlay recordings, and a feasibility study conducted with 60 infants indicates that they can learn the contingency between their vocalisations and the appearance of shapes on the screen in one five minute BabblePlay session. BabblePlay meets the specification of being a simple and easy-to-use app. It has been shown to be a promising tool for research on infant language development that could lead to its use in home and professional environments to demonstrate the importance of immediate reward for vocal utterances to increase vocalisations in infants.

A child's first words mark the emergence of a uniquely human ability. Theories of the developmental steps that pave the way for word production have proposed that either vocal or gestural precursors are key. These accounts were tested by assessing the developmental synchrony in the onset of babbling, pointing, and word production for 46 infants observed monthly between the ages of 9 and 18 months. Babbling and pointing did not develop in tight synchrony and babble onset alone predicted first words. Pointing and maternal education emerged as predictors of lexical knowledge only in relation to a measure taken at 18 months. This suggests a far more important role for early phonological development in the creation of the lexicon than previously thought.

The word segmentation paradigm originally designed by Jusczyk and Aslin (1995) has been widely used to examine how infants from the age of 7.5 months can extract novel words from continuous speech. Here we report a series of 13 studies conducted independently in two British laboratories, showing that British English-learning infants aged 8-10.5 months fail to show evidence of word segmentation when tested in this paradigm. In only one study did we find evidence of word segmentation at 10.5 months, when we used an exaggerated infant-directed speech style. We discuss the impact of variations in infant-directed style within and across languages in the course of language acquisition.

Researchers disagree as to the importance for infant language learning of isolated words, which occur relatively rarely in input speech. Brent and Siskind (2001) showed that the first words infants produce are words their mothers used most frequently in isolation. Here we investigate the long-term effects of presentation mode on recognition memory for word forms. In two experiments we assess whether 12-month-old infants remember novel words presented in the home, over a three-week period: (i) in isolation or (ii) sentence-finally. When tested with word lists infants recognize words that had been presented in isolation, but not those that had been presented sentence-finally. They fail to recognise the trained words when tested with a segmentation task, regardless of presentation mode during the training. Our results indicate that the relatively small proportion of words produced in isolation in the input likely play a disproportionate role in the early period of language learning.

This study aims to elucidate the factors that affect the robustness of word-form representations by exploring the relative influence of lexical stress and segmental identity (consonant versus vowel) on infant word recognition. Our main question was which changes to the words may go unnoticed and which may lead the words to be unrecognizable. One-hundred 11-month-old Hebrew-learning infants were tested in two experiments using the Central Fixation Procedure. In Experiment 1, 20 infants were presented with iambic Familiar and Unfamiliar words. The infants listened longer to Familiar than to Unfamiliar words, indicating their recognition of frequently heard word forms. In Experiment 2 four groups of 20 infants each were tested in each of four conditions involving altered iambic Familiar words contrasted with iambic Unfamiliar nonwords. In each condition one segment in the Familiar word was changed – either a consonant or a vowel, in either the first (unstressed) or the second (stressed) syllable. In each condition recognition of the Familiar words despite the change indicates a less accurate or less well-specified representation. Infants recognized Familiar words despite changes to the weak (first) syllable, regardless of whether the change involved a consonant or a vowel (conditions 2a, 2c). However, a change of either consonant or vowel in the stressed (second) syllable blocked word recognition (conditions 2b, 2d). These findings support the proposal that stress pattern plays a key role in early word representation, regardless of segmental identity.

An order effect was found in English infants’ discrimination of an Urdu contrast. In Experiment 1 7- and 11-month-old English infants were tested on the Urdu contrast between the affricates /tʃʰ/ and /tʃ/. The order of presentation was counterbalanced: At each age half the infants were habituated to the aspirated and tested on the unaspirated affricate, the other half habituated to the unaspirated and tested on the aspirated. As expected, younger infants discriminated the contrast whereas older infants did not, showing the expected decline in discrimination. Interestingly, order of presentation seemed to affect the older infants’ response. Experiment 2 tested the order effect directly. The results showed no asymmetry in the performance of 7-month olds but clear asymmetry in that of 11-month-olds, who discriminated the contrast only when the non-English-like aspirated affricate was presented first. Experiment 3 tested adult native-speakers of both Urdu and English. Although the English listeners showed a reduced sensitivity to the contrast, there was no effect due to order of presentation of the stimuli in either adult group. The finding of an asymmetry in the infants suggests that infants’ perceptual narrowing for speech sounds may be a more complex phenomenon than has generally been assumed.

The ability of infants to recognize phonotactic patterns in their native language is widely acknowledged. However, the specific ability of infants to recognize patterns created by nonadjacent vowels in words has seldom been investigated. In Semitic languages such as Hebrew, groups of multisyllabic words are identical in their nonadjacent vowel sequences and stress position but differ in the consonants interposed between the vowels. The goals of this study were to assess whether infants learning Hebrew show a preference for (1) a nonadjacent vocalic pattern or template, common in Hebrew nouns (CeCeC), over a nonattested nonadjacent vocalic pattern (CoCoC), and (2) a nonadjacent vocalic pattern common in Hebrew words (CaCoC) over an existing but less common pattern (CaCeC). Twenty Hebrew-learning infants aged 8 to 11 months were presented with lists of nonsense words featuring the first two patterns (Experiment 1), and 20 were presented with nonsense words featuring the second two patterns (Experiment 2). The results showed longer listening to CeCeC than to CoCoC lists and to CaCoC than to CaCeC lists, suggesting that infants recognized the common nonadjacent vocalic patterns in both cases. The study thus demonstrates that Hebrew-learning infants are able to disregard the intervening consonants within words and generalize their vocalic pattern to previously unheard nonwords, whether this pattern includes identical or different vowels and regardless of the rhythmic pattern of the word (trochaic or iambic). Analysis of the occurrence of the relevant vowel patterns in input speech in three Hebrew corpora (two addressed to children and one to adults) suggests that exposure to these patterns in words underlies the infants' preferences.

Studies of phonological development that combine speech-processing experiments with observation and analysis of production remain rare, although production experience is necessarily relevant to developmental advance. Here we focus on three proposals regarding the relationship of production to word learning: (1) Articulatory filter: The hypothesis that children are influenced in noticing words in input speech by their resemblance to patterns they can produce has recently received experimental support. (2) Systematization and regression: It is proposed that the decline in accuracy that follows first-word production is the consequence of an increase in systematicity (with renewed accuracy emerging only later). (3) Word-production experience facilitates new word learning: Evidence that expressive vocabulary growth in itself facilitates new word learning supports the idea that knowledge is gradient, involving increases in stability and reliability with repeated exposure and use.

Maternal responsiveness has been positively related with a range of socio-emotional and cognitive outcomes including language. A substantial body of research has explored different aspects of verbal responsiveness. However, perhaps because of the many ways in which it can be operationalised, there is currently a lack of consensus around what type of responsiveness is most helpful for later language development. The present study sought to address this problem by considering both the semantic and temporal dimensions of responsiveness on a single cohort while controlling for level of parental education and the overall amount of communication on the part of both the caregiver and the infant. We found that only utterances that were both semantically appropriate and temporally linked to an infant vocalization were related to infant expressive vocabulary at 18 months.

The headturn preference procedure was used to test 18 infants on their response to three different passages chosen to reflect their individual production patterns. The passages contained nonwords with consonants in one of three categories: (a) often produced by that infant (‘own’), (b) rarely produced by that infant but common at that age (‘other’), and (c) not generally produced by infants. Infants who had a single ‘own’ consonant showed no significant preference for either ‘own’ (a) or ‘other’ (b) passages. In contrast, infants’ with two ‘own’ consonants exhibited greater attention to ‘other’ passages (b). Both groups attended equally to the passage featuring consonants rarely produced by infants of that age (c). An analysis of a sample of the infant-directed speech ruled out the mothers’ speech as a source of the infant preferences. The production-based shift to a focus on the ‘other’ passage suggests that nascent production abilities combine with emergent perceptual experience to facilitate word learning.

Carol Stoel-Gammon has made a real contribution in bringing together two fields that are not generally jointly addressed. Like Stoel-Gammon, we have long focused on individual differences in phonological development (e.g. Vihman, Ferguson & Elbert, 1986; Vihman, Boysson-Bardies, Durand & Sundberg, 1994; Keren-Portnoy, Majorano & Vihman, 2008). And like her, we have been closely concerned with the relationship between lexical and phonological learning. Accordingly, we will focus our discussion on two areas covered by Stoel-Gammon (this issue) on which our current work may shed some additional light.

Purpose In this study, the authors looked for effects of vocal practice on phonological working memory. Method A longitudinal design was used, combining both naturalistic observations and a nonword repetition test. Fifteen 26-month-olds (12 of whom were followed from age 11 months) were administered a nonword test including real words, “standard” nonwords (identical for all children), and nonwords based on individual children’s production inventory ( in and out words). Results A strong relationship was found between (a) length of experience with consonant production and (b) nonword repetition and between (a) differential experience with specific consonants through production and (b) performance on the in versus out words. Conclusions Performance depended on familiarity with words or their subunits and was strongest for real words, weaker for in words, and weakest for out words. The results demonstrate the important role of speech production in the construction of phonological working memory.

Children raised in the home as English or Welsh monolinguals or English–Welsh bilinguals were tested on untrained word form recognition using both behavioral and neurophysiological procedures. Behavioral measures confirmed the onset of a familiarity effect at 11 months in English but failed to identify it in monolingual Welsh infants between 9 and 12 months. In the neurophysiological procedure the familiarity effect was detected as early as 10 months in English but did not reach significance in monolingual Welsh. Bilingual children showed word form familiarity effects by 11 months in both languages and also revealed an online time course for word recognition that combined effects found for monolingual English and Welsh. To account for the findings, accentual, grammatical, and sociolinguistic differences between English and Welsh are considered.

This study suggests that familiarity and novelty preferences in infant experimental tasks can in some instances be interpreted together as a single indicator of language advance. We provide evidence to support this idea based on our use of the auditory headturn preference paradigm to record responses to words likely to be either familiar or unfamiliar to infants. Fifty-nine 10-month-old infants were tested. The task elicited mixed preferences: familiarity (longer average looks to the words likely to be familiar to the infants), novelty (longer average looks to the words likely to be unfamiliar) and no-preference (similar-length of looks to both type of words). The infants who exhibited either a familiarity or a novelty response were more advanced on independent indices of phonetic advance than the infants who showed no preference. In addition, infants exhibiting novelty responses were more lexically advanced than either the infants who exhibited familiarity or those who showed no-preference. The results provide partial support for Hunter and Ames’ (1988) developmental model of attention in infancy and suggest caution when interpreting studies indexed to chronological age.

Whole-word phonology is a particular approach to early phonological development. This volume is designed to bring together the classic papers which gave rise to it in the 1970s and current studies that build on and extend the model, which in essence took an emergentist and usage-based stance before its time; the book will make no attempt to cover other approaches to phonological development in any systematic way. Many of the papers, including Vihman and Croft (2007, this volume, Chapter 2), with which we begin, use the term “template” to refer to child-specific word patterns identifiable within the first year of word use. Templates, referred to sporadically in the earlier developmental literature (e.g.,Menn 1983, this volume, Chapter 6) and given formal status for adult linguistic analyses in Prosodic Morphology (McCarthy and Prince 1995), are a more focused expression of the ideas formulated by Waterson (1971, this volume, Chapter 3), Ferguson and Farwell (1975, this volume, Chapter 4), and Macken (1979, this volume, Chapter 5), which provided the core of the whole-word phonology idea (see Vihman and Croft 2007, this volume, Chapter 2, for a summary of the basic arguments). This volume is restricted to the study of early word production and the phonological patterning that can be seen in that domain. The year in which the first of our “setting papers” was written – Waterson (1971, this volume, Chapter 3) – also marks the year of publication of the first study of infant speech perception (Eimas, Siqueland, Jusczyk, andVigorito 1971). Since then, perception studies have solidly documented infants’ remarkable early discriminatory capacities and the rapid advances in knowledge of the ambient language that follow over the first year of life (see Jusczyk 1997; Kuhl 2004; and Vihman forthcoming 2014 for reviews), while numerous studies demonstrating infant statistical learning (in language and other areas) from an early age have expanded our understanding of the learning mechanism that may underlie those advances (see Thiessen and Saffran 2007, and Johnson and Tyler 2010 for alternative positions on the role of statistical learning; Vihman forthcoming 2014: ch. 5 provides an overview). In addition, several distinct methodological procedures have been used to trace and explore the nature of early word-form learning over the first two years of life. The resultant studies are of evident relevance to phonological development but none are included here, as the addition of even a few would result in a far

1. Introduction Marilyn M. Vihman and Tamar Keren-Portnoy Part I. The Current Framework: 2. Phonological development: toward a 'radical' templatic phonology Marilyn Vihman and William Croft Part II. Setting Papers: 3. Child phonology: a prosodic view Natalie Waterson 4. Words and sounds in early language acquisition Charles A. Ferguson and Carol B. Farwell 5. Developmental reorganization of phonology: a hierarchy of basic units of acquisition Marlys A. Macken 6. Development of articulatory, phonetic, and phonological capabilities Lise Menn Part III. Cross-Linguistic Studies: 7. One idiosyncratic strategy in the acquisition of phonology T. M. S. Priestly 8. Phonological reorganization: a case study Marilyn M. Vihman and Shelley L. Velleman 9. How abstract is child phonology? Towards an integration of linguistic and psychological approaches Marilyn M. Vihman, Shelley L. Velleman and Lorraine McCune 10. Beyond early words: word template development in Brazilian Portuguese Daniela Oliveira-Guimaraes 11. Templates in French Sophie Wauquier and Naomi Yamaguchi 12. The acquisition of consonant clusters in Polish: a case study Marta Szreder 13. Geminate template: a model for first Finnish words Tuula Savinainen-Makkonen 14. Influence of geminate structure on early Arabic templatic patterns Ghada Khattab and Jalal Al-Tamimi 15. Lexical frequency effects on phonological development: the case of word production in Japanese Mitsuhiko Ota Part IV. Perspectives and Challenges: 16. A view from developmental psychology Lorraine McCune 17. Challenges to theories, charges to a model: the linked-attractor model of phonological development Lise Menn, Ellen Schmidt and Brent Nicholas.

This paper sets out to show how facilitation between different clause structures operates over time in syntax acquisition. The phenomenon of facilitation within given structures has been widely documented, yet inter-structure facilitation has rarely been reported so far. Our findings are based on the naturalistic production corpora of six toddlers learning Hebrew as their first language. We use regression analysis, a method that has not been used to study this phenomenon. We find that the proportion of errors among the earliest produced clauses in a structure is related to the degree of acceleration of that structure's learning curve; that with the accretion of structures the proportion of errors among the first clauses of new structures declines, as does the acceleration of their learning curves. We interpret our findings as showing that learning new syntactic structures is made easier, or facilitated, by previously acquired ones.

This study assesses the extent of phonetic continuity between babble and words in four Italian children followed longitudinally from 0 ; 9 or 0 ; 10 to 2 ; 0 – two with relatively rapid and two with slower lexical growth. Prelinguistic phonetic characteristics, including both (a) consistent use of specific consonants and (b) age of onset and extent of consonant variegation in babble, are found to predict rate of lexical advance and to relate to the form of the early words. In addition, each child's lexical profile is analyzed to test the hypothesis of non-linearity in phonological development. All of the children show the expected pattern of phonological advance: Relatively accurate first word production is followed by lexical expansion, characterized by a decrease in accuracy and an increase of similarity between word forms. We interpret such a profile as reflecting the emergence of word templates, a first step in phonological organization.