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Rhythm perception helps young infants find structure in both speech and music. However, it remains unknown whether categorical perception of suprasegmental linguistic rhythm signaled by a co-variation of multiple acoustic cues can be modulated by prior between- (music) and within-domain (language) experience. Here we tested 6-month-old German-learning infants' ability to have a categorical perception of lexical stress, a linguistic prominence signaled through the co-variation of pitch, intensity, and duration. By measuring infants' pupil size, we find that infants as a group fail to perceive co-variation of these acoustic cues as categorical. However, at an individual level, infants with above-average exposure to music and language at home succeeded. Our results suggest that early exposure to music and infant-directed language can boost the categorical perception of prominence.

Successful word recognition requires that listeners attend to differences that are phonemic in the language while also remaining flexible to the variation introduced by different voices and accents. Previous work has demonstrated that American-English-learning 19-month-olds are able to balance these demands: although one-off one-feature mispronunciations typically disrupt English-learning toddlers' lexical access, they no longer do after toddlers are exposed to a novel accent in which these changes occur systematically. The flexibility to deal with different types of variation may not be the same for toddlers learning different first languages, however, as language structure shapes early phonological biases. We examined French-learning 19-month-olds' sensitivity and adaptation to a novel accent that shifted either the standard pronunciation of /a/ from [a] to [open-mid front unrounded vowel] (Experiment 1) or the standard pronunciation of /p/ from [p] to [t] (Experiment 2). In Experiment 1, French-learning toddlers recognized words with /a/ produced as [open-mid front unrounded vowel], regardless of whether they were previously exposed to an accent that contained this vowel shift or not. In Experiment 2, toddlers did not recognize words with /p/ pronounced as [t] at test unless they were first familiarized with an accent that contained this consonant shift. These findings are consistent with evidence that French-learning toddlers privilege consonants over vowels in lexical processing. Together with previous work, these results demonstrate both differences and similarities in how French- and English-learning children treat variation, in line with their language-specific phonological biases.

Infants attune to their native language during the first two years of life, as attested by decreases in the processing of nonnative phonological sounds and reductions in the range of possible sounds accepted as labels for native words. The present study shows that French-learning infants aged 1;8 can learn new words in an unfamiliar language, Cantonese, after just 6 repetitions of each word. This shows that word learning in a nonnative language remains possible during the second year of life even in a nonnative language that is typologically distinct from the native language.

Preterm birth (<37 gestational weeks) is associated with long-term risks for health and neurodevelopment, but recently, studies have also started exploring how preterm birth affects early language development in the 1st year of life. Because the timing and quality of auditory and visual input is very different for preterm versus full-term infants, audiovisual speech perception in early development may be particularly sensitive to preterm birth. We tested extremely preterm to late preterm infants at 8 months postnatal age (28 to 36 weeks of gestation), as well as 2 full-term comparison groups with similar postnatal (8 months) and maturational (6 months) ages, on visual scanning of a video showing a French-English bilingual woman speaking in the infants' native language (French) and a nonnative language (English). Preterm infants showed similar scanning patterns for both languages, failing to differentiate between native and nonnative languages in their looking, unlike both groups of full-term infants, who looked more to the eyes than the mouth for the native language compared with the nonnative language. No clear relationship between scanning patterns and degree of prematurity was found. These findings are the first to show that audiovisual speech perception is affected in even later-born preterm infants, thus identifying a particularly sensitive deficit in early speech processing. Further research will need to investigate how preterms' special vulnerability in audiovisual speech processing may contribute to the other language difficulties found in these populations.

Individual variability in infant's language processing is partly explained by environmental factors, like the quantity of parental speech input, as well as by infant-specific factors, like speech production. Here, we explore how these factors affect infant word segmentation. We used an artificial language to ensure that only statistical regularities (like transitional probabilities between syllables) could cue word boundaries, and then asked how the quantity of parental speech input and infants' babbling repertoire predict infants' abilities to use these statistical cues. We replicated prior reports showing that 8-month-old infants use statistical cues to segment words, with a preference for part-words over words (a novelty effect). Crucially, 8-month-olds with larger novelty effects had received more speech input at 4 months and had greater production abilities at 8 months. These findings establish for the first time that the ability to extract statistical information from speech correlates with individual factors in infancy, like early speech experience and language production. Implications of these findings for understanding individual variability in early language acquisition are discussed.

Characterizing the nature of linguistic representations and how they emerge during early development is a central goal in the cognitive science of language. One area in which this development plays out is in the acquisition of dependencies--relationships between co-occurring elements in a word, phrase, or sentence. These dependencies often involve multiple levels of representation and abstraction, built up as infants gain experience with their native language. The authors used the Headturn Preference Procedure to systematically investigate the early acquisition of 1 such dependency, the agreement between a subject and verb in French, at 6 different ages between 14 and 24 months. The results reveal a complex developmental trajectory that provides the first evidence that infants might indeed progress through distinct stages in the acquisition of this nonadjacent dependency. The authors discuss how changes in general cognition and representational knowledge (from reflecting surface statistics to higher-level morphological features) might account for their findings. These findings highlight the importance of studying language acquisition at close time intervals over a substantial age range.

The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two non-adjacent vowels. Experiments 1 and 2 show that a preference for PA over AP (anterior-posterior) words emerges between 10 and 13 months in French-learning infants. Control experiments show that this bias cannot be explained by adjacent or positional preferences. The present study demonstrates that infants become sensitive to non-adjacent vocalic distributional regularities between 10 and 13 months, showing the existence of a delay for the acquisition of non-adjacent vocalic regularities compared to equivalent non-adjacent consonantal regularities. These results are consistent with the CV hypothesis, according to which consonants and vowels play different roles at different linguistic levels.

Infants have remarkable abilities to learn several languages. However, phonological acquisition in bilingual infants appears to vary depending on the phonetic similarities or differences of their two native languages. Many studies suggest that learning contrasts with different realizations in the two languages (e.g., the /p/, /t/, /k/ stops have similar VOT values in French, Spanish, Italian and European Portuguese, but can be confounded with the /b/, /d/, /g/ in German and English) poses a particular challenge. The current study explores how similarity or difference in the realization of phonetic contrasts affects word-learning outcomes. Bilingual infants aged 16 months were tested on their capacity to learn pairs of new words, differing by a phonological feature (voicing versus place) on their initial consonant. Two groups of infants were considered: bilinguals exposed to languages (French and either Spanish, Italian or European Portuguese) in which the contrasts tested are realized relatively similarly ("similar contrast" group) and bilinguals exposed to languages (French and either English or German) in which the contrasts are realized very differently ("different contrast" group). In the present word-learning situation, the "similar contrast" bilinguals successfully processed the relevant phonetic detail of the word forms, while the "different contrast" bilinguals failed. The present pattern reveals the impact on word learning of phonological differences between the two languages, which is consistent with studies reporting slight time course differences among bilinguals in phonological acquisition. In line with a larger literature on bilingual acquisition, these results provide further evidence that linguistic similarity or difference in the two languages influences the pattern of bilingual acquisition.

The present study explored whether the phonological bias favoring consonants found in French-learning infants and children when learning new words (Havy & Nazzi, 2009; Nazzi, 2005) is language-general, as proposed by Nespor, Peña and Mehler (2003), or varies across languages, perhaps as a function of the phonological or lexical properties of the language in acquisition. To do so, we used the interactive word-learning task set up by Havy and Nazzi (2009), teaching Danish-learning 20-month-olds pairs of phonetically similar words that contrasted either on one of their consonants or one of their vowels, by either one or two phonological features. Danish was chosen because it has more vowels than consonants, and is characterized by extensive consonant lenition. Both phenomena could disfavor a consonant bias. Evidence of word-learning was found only for vocalic information, irrespective of whether one or two phonological features were changed. The implication of these findings is that the phonological biases found in early lexical processing are not language-general but develop during language acquisition, depending on the phonological or lexical properties of the native language.

Recently, several studies have argued that infants capitalize on the statistical properties of natural languages to acquire the linguistic structure of their native language, but the kinds of constraints which apply to statistical computations remain largely unknown. Here we explored French-learning infants' perceptual preference for labial-coronal (LC) words over coronal-labial words (CL) words (e.g. preferring "bat" over "tab") to determine whether this phonotactic preference is based on the acquisition of the statistical properties of the input based on a single phonological feature (i.e. place of articulation), multiple features (i.e. place and manner of articulation), or individual consonant pairs. Results from four experiments revealed that infants had a labial-coronal bias for nasal sequences (Experiment 1) and for all plosive sequences (Experiments 2 and 4) but a coronal-labial bias for all fricative sequences (Experiments 3 and 4), independently of the frequencies of individual consonant pairs. These results establish for the first time that constellations of multiple phonological features, defining broad consonant classes, constrain the early acquisition of phonotactic regularities of the native language.

Following the proposal that consonants are more involved than vowels in coding the lexicon (Nespor, Peña & Mehler, 2003), an early lexical consonant bias was found from age 1;2 in French but an equal sensitivity to consonants and vowels from 1;0 to 2;0 in English. As different tasks were used in French and English, we sought to clarify this ambiguity by using an interactive word-learning study similar to that used in French, with British-English-learning toddlers aged 1;4 and 1;11. Children were taught two CVC labels differing on either a consonant or vowel and tested on their pairing of a third object named with one of the previously taught labels, or part of them. In concert with previous research on British-English toddlers, our results provided no evidence of a general consonant bias. The language-specific mechanisms explaining the differential status for consonants and vowels in lexical development are discussed.

Six experiments explored Parisian French-learning infants' ability to segment bisyllabic words from fluent speech. The first goal was to assess whether bisyllabic word segmentation emerges later in infants acquiring European French compared to other languages. The second goal was to determine whether infants learning different dialects of the same language have partly different segmentation abilities, and whether segmenting a non-native dialect has a cost. Infants were tested on standard European or Canadian French stimuli, in the word-passage or passage-word order. Our study first establishes an early onset of segmentation abilities: Parisian infants segment bisyllabic words at age 0;8 in the passage-word order only (revealing a robust order of presentation effect). Second, it shows that there are differences in segmentation abilities across Parisian and Canadian French infants, and that there is a cost for cross-dialect segmentation for Parisian infants. We discuss the implications of these findings for understanding word segmentation processes.

Purpose: In this study, the authors explored whether French-learning infants use nonadjacent phonotactic regularities in their native language, which they learn between the ages of 7 and 10 months, to segment words from fluent speech. Method: Two groups of 20 French-learning infants were tested using the head-turn preference procedure at 10 and 13 months of age. In Experiment 1, infants were familiarized with 2 passages: 1 containing a target word with a frequent nonadjacent phonotactic structure and the other containing a target word with an infrequent nonadjacent phonotactic structure in French. During the test phase, infants were presented with 4 word lists: 2 containing the target words presented during familiarization and 2 other control words with the same phonotactic structure. In Experiment 2, the authors retested infants' ability to segment words with the infrequent phonotactic structure. Results: Ten- and 13-month-olds were able to segment words with the frequent phonotactic structure, but it is only by 13 months, and only under the circumstances of Experiment 2, that infants could segment words with the infrequent phonotactic structure. Conclusion: These results provide new evidence showing that infant word segmentation is influenced by prior nonadjacent phonotactic knowledge. (Contains 2 figures, 1 table, and 2 footnotes.)

Previous work has shown that preterm infants are at higher risk for cognitive/language delays than full-term infants. Recent studies, focusing on prosody (i.e. rhythm, intonation), have suggested that prosodic perception development in preterms is indexed by maturational rather than postnatal/listening age. However, because prosody is heard in-utero, and preterms thus lose significant amounts of prenatal prosodic experience, both their maturation level and their prosodic experience (listening age) are shorter than that of full-terms for the same postnatal age. This confound does not apply to the acquisition of phonetics/phonotactics (i.e. identity and order of consonants/vowels), given that consonant differences in particular are only perceived after birth, which could lead to a different developmental pattern. Accordingly, we explore the possibility that consonant-based phonotactic perception develops according to listening age. Healthy French-learning full-term and preterm infants were tested on the perception of consonant sequences in a behavioral paradigm. The pattern of development for full-term infants revealed that 7-month-olds look equally at labial-coronal (i.e. /pat/) compared to coronal-labial sequences (i.e. /tap/), but that 10-month-olds prefer the labial-coronal sequences that are more frequent in the French lexicon. Preterm 10-month-olds (having 10 months of phonetic listening experience but 7 months of maturational age) behaved as full-term 10-month-olds. These results establish that preterm developmental timing for consonant-based phonotactic acquisition is based on listening age (experience with input). This questions the interpretation of previous results on prosodic acquisition in terms of maturational constraints, and raises the possibility that different constraints apply to the acquisition of different phonological subcomponents. (Contains 3 tables and 2 figures.)

Transitional Probability (TP) computations are regarded as a powerful learning mechanism that is functional early in development and has been proposed as an initial bootstrapping device for speech segmentation. However, a recent study casts doubt on the robustness of early statistical word-learning. Johnson and Tyler (2010) showed that when 8-month-olds are presented with artificial languages where TPs between syllables are reliable cues to word boundaries but that contain words of varying length, infants fail to show word segmentation. Given previous evidence that familiar words facilitate segmentation (Bortfeld, Morgan, Golinkoff, & Rathbun, 2005), we investigated the conditions under which 8-month-old French-learning infants can succeed in segmenting an artificial language. We found that infants can use TPs to segment a language of uniform length words (Experiment 1) and a language of nonuniform length words containing the familiar word "maman" (/mama/, mommy in French; Experiment 2), but not a similar language of nonuniform length words containing the pseudo-word /mama/ (Experiment 3). We interpret these findings as evidence that 8-month-olds can use familiar words and TPs in combination to segment fluent speech, providing initial evidence for 8-month-olds' ability to combine top-down and bottom-up speech segmentation procedures. (Contains 2 tables, 1 figure, and 2 footnotes.)

Languages instantiate many different kinds of dependencies, some holding between adjacent elements and others holding between nonadjacent elements. In the domain of phonology-phonotactics, sensitivity to adjacent dependencies has been found to appear between 6 and 10 months. However, no study has directly established the emergence of sensitivity to nonadjacent phonological dependencies in the native language. The present study focuses on the emergence of a perceptual Labial-Coronal (LC) bias, a dependency involving two nonadjacent consonants. First, Experiment 1 shows that a preference for monosyllabic consonant-vowel-consonant LC words over CL (Coronal-Labial) words emerges between 7 and 10 months in French-learning infants. Second, two experiments, presenting only the first or last two phonemes of the original stimuli, establish that the LC bias at 10 months cannot be explained by adjacent dependencies or by a preference for more frequent coronal consonants (Experiment 2a & b). At 7 months, by contrast, infants appear to react to the higher frequency of coronal consonants (Experiment 3a & b). The present study thus demonstrates that infants become sensitive to nonadjacent phonological dependencies between 7 and 10 months. It further establishes a change between these two ages from sensitivity to local properties to nonadjacent dependencies in the phonological domain. (Contains 3 footnotes, 1 figure and 7 tables.)

A visual fixation study tested whether 7-month-olds can discriminate between different talkers. The infants were first habituated to talkers producing sentences in either a familiar or unfamiliar language, then heard test sentences from previously unheard speakers, either in the language used for habituation, or in another language. When the language at test mismatched that in habituation, infants always noticed the change. When language remained constant and only talker altered, however, infants detected the change only if the language was the native tongue. Adult listeners with a different native tongue from the infants did not reproduce the discriminability patterns shown by the infants, and infants detected neither voice nor language changes in reversed speech; both these results argue against explanation of the native-language voice discrimination in terms of acoustic properties of the stimuli. The ability to identify talkers is, like many other perceptual abilities, strongly influenced by early life experience.

This study examines French-learning infants' sensitivity to grammatical non-adjacent dependencies involving subject-verb agreement (e.g., "le/les garcons lit/lisent" "the boy(s) read(s)") where number is audible on both the determiner of the subject DP and the agreeing verb, and the dependency is spanning across two syntactic phrases. A further particularity of this subsystem of French subject-verb agreement is that number marking on the verb is phonologically highly irregular. Despite the challenge, the HPP results for 24- and 18-month-olds demonstrate knowledge of both number dependencies: between the singular determiner le and the non-adjacent singular verbal forms and between the plural determiner les and the non-adjacent plural verbal forms. A control experiment suggests that the infants are responding to known verb forms, not phonological regularities. Given the paucity of such forms in the adult input documented through a corpus study, these results are interpreted as evidence that 18-month-olds have the ability to extract complex patterns across a range of morphophonologically inconsistent and infrequent items in natural language. (Contains 10 tables and 3 figures.)

To investigate the interaction between segmental and supra-segmental stress-related information in early word learning, two experiments were conducted with 20- to 24-month-old English-learning children. In an adaptation of the object categorization study designed by Nazzi and Gopnik (2001), children were presented with pairs of novel objects whose labels differed by their initial consonant (Experiment 1) or their medial consonant (Experiment 2). Words were produced with a stress initial (trochaic) or a stress final (iambic) pattern. In both experiments successful word learning was established when the to-be-remembered contrast was embedded in a stressed syllable, but not when embedded in unstressed syllables. This was independent of the overall word pattern, trochaic or iambic, or the location of the phonemic contrast, word-initial or -medial. Results are discussed in light of the use of phonetic information in early lexical acquisition, highlighting the role of lexical stress and ambisyllabicity in early word processing.

Using a name-based categorization task, Nazzi found in 2005 that French-learning 20-month-olds can make use of one-feature consonantal contrasts between new labels but fail to do so with one-feature vocalic contrasts. This asymmetry was interpreted as developmental evidence for the proposal that consonants play a more important role than vowels at the lexical level. In the current study using the same task, we first show that by 30 months French-learning infants can make use of one-feature vocalic contrasts (e.g., /pize/-/pyze/). Second, we show that in a situation where infants must neglect either a consonantal one-feature change or a vocalic one-feature change (e.g., match a /pide/ with either a /tide/ or a /pyde/), both French- and English-learning 30-month-olds choose to neglect the vocalic change rather than the consonantal change. We argue that these results suggest that by 30 months of age, infants still give less weight to vocalic information than to consonantal information in a lexically related task even though they are able to process fine vocalic information. (Contains 3 figures and 3 tables.)

Previous research using the name-based categorization task has shown that 20-month-old infants can simultaneously learn 2 words that only differ by 1 consonantal feature but fail to do so when the words only differ by 1 vocalic feature. This asymmetry was taken as evidence for the proposal that consonants are more important than vowels at the lexical level. This study explores this consonant-vowel asymmetry in 16-month-old infants, using an interactive word learning task. It shows that the pattern of the 16-month-olds is the same as that of the 20-month-olds. Infants succeeded with 1-feature consonantal contrasts (either place or voicing) but were at chance level with 1-feature vocalic contrasts (either place or height). These results thus contribute to a growing body of evidence establishing, from early infancy to adulthood, that consonants and vowels have different roles in lexical acquisition and processing. (Contains 3 figures, 1 table and 1 footnote.)

Use of precise consonantal information while learning new words has been established for onset consonants in previous studies, which showed that infants as young as 16 to 20 months of age can simultaneously learn two new words that differ only by a syllable-initial consonant (Havy & Nazzi, 2009; Nazzi, 2005; Nazzi & New, 2007; Werker, Fennell, Corcoran, & Stager, 2002). However, there is no systematic evidence to show whether specific phonetic information in other positions within the syllable can be used while learning new words. To the contrary, Nazzi (2005) found that when tested using the same task, 20-month-olds can learn two words that differ only by a consonant, but fail to do so if they differ only by a vowel, leaving open the possibility that specificity is limited to syllable-onset positions. Accordingly, the present study evaluated 20-month-olds' ability to learn two words that differ only by a consonant in either onset or coda position. Infants succeeded for both positions, ruling out the possibility that only syllable-onset positions are specified. This further suggests that the previously reported consonant/vowel asymmetry cannot be fully explained by syllable-onset positional effects. Additionally, the present study evaluated whether words following a predominant labial-coronal pattern would be easier to learn than less frequent coronal-labial words. It failed to obtain any such evidence. (Contains 2 figures, 2 tables, and 2 footnotes.)

Previous research has shown that 20-month-old infants can simultaneously learn two words that only differ by one of their consonants, but fail to do so when the words differ only by one of their vowels. This asymmetry was interpreted as developmental evidence for the proposal that consonants play a more important role than vowels in lexical specification. However, the consonant/vowel distinction was confounded with another distinction, that of the continuous status of the phonemes used (discontinuous stop consonants versus continuous vowels). The present study investigated 20-month-olds' use of phonetic specificity while simultaneously learning two words that differ by a continuous consonant. The results obtained parallel those previously found for stop consonants, confirming the original claim of an asymmetry between the roles of consonants and vowels at the lexical level.

Four experiments explored French-learning infants' ability to segment words from fluent speech. The focus was on bisyllabic words to investigate whether infants segment them as whole words or segment each syllable individually. No segmentation effects were found in 8-month-olds. Twelve-month-olds segmented individually both the final syllables and, under appropriate test conditions, the initial syllables of these bisyllabic words, but failed to segment bisyllabic words as whole units. The opposite pattern was observed at 16 months: final syllables were not segmented, while there was evidence that the words were segmented as whole units. The present findings are consistent with the proposal that the syllable is a unit of prosodic segmentation in French, therefore introducing evidence from a syllable-based language in support of the more general hypothesis that the emergence of segmentation abilities differs crosslinguistically as a function of the rhythmic class of the language in acquisition.

The present study explores the issue of the use of phonetic specificity in the process of learning new words at 20 months of age. The procedure used follows Nazzi and Gopnik [Nazzi, T., & Gopnik, A. (2001). Linguistic and cognitive abilities in infancy: When does language become a tool for categorization? "Cognition," 80, B11-B20]. Infants were first presented with triads of perceptually dissimilar objects, which were given made-up names, two of the objects receiving the same name. Then, word learning was evaluated through object selection/categorization. Tests involved phonetically different words (e.g. [pize] vs. [mora], Experiment 1), words differing minimally on their onset consonant (e.g. [pize] vs. [tize], Experiment 2a), and conditions which had never been tested before: non-initial consonantal contrasts (e.g. [pide] vs. [pige], Experiment 2b), and vocalic contrasts (e.g. [pize] vs. [pyze]; [pize] vs. [paze]; [pize] vs. [pizu], Experiments 3a-c). Results differed across conditions: words could be easily learnt in the phonetically different condition, and were learnt, though to a lesser degree, in both the initial and non-initial minimal consonant contrast; however, infants' global performance on all three vocalic contrasts was at chance level. The present results shed new light regarding the specificity of early words, and raise the possibility of different contributions for vowels and consonants in early word learning.

Two experiments sought to extend the demonstration of English-learning infants' abilities to segment nouns from fluent speech to a new lexical class: verbs. Moreover, we explored whether two factors previously shown to influence noun segmentation, stress pattern (strong-weak or weak-strong) and type of initial phoneme (consonant or vowel), also influence verb segmentation. Our results establish the early emergence of verb segmentation in English: by 13.5 months for strong-weak consonant- or vowel-initial verbs and for weak-strong consonant-initial verbs; and by 16.5 months for weak-strong verbs beginning with a vowel. This generalizes previous reports of early segmentation to a new lexical class, thereby providing additional evidence that segmentation is likely to contribute to lexical acquisition. The effects of stress pattern and onset type found are similar to those previously obtained for nouns, in that verbs with a weak-strong stress pattern and verbs beginning with a vowel appear to be at a disadvantage in segmentation. Finally, we present prosodic analyses that suggest a possible effect of prosodic boundary and pitch accent distribution on segmentation. These prosodic differences potentially explain a developmental lag in verb segmentation observed in the present study compared to earlier findings for noun segmentation. (Contains 1 table, 2 figures and 5 footnotes.)

Evaluated infants' ability to form new object categories based on either visual or naming information at 16 and 20 months using an object manipulation task. Found that infants at both ages showed evidence of using visual information to categorize the objects. Only 20-month-olds used naming information. Found a correlation between vocabulary size and name-based categorization among the 20-month-olds. (Author/KB)

Infants begin to segment word forms from fluent speech—a crucial task in lexical processing—between 4 and 7 months of age. Prior work has established that infants rely on a variety of cues available in the speech signal (i.e., prosodic, statistical, acoustic‐segmental, and lexical) to accomplish this task. In two experiments with French‐learning 6‐ and 10‐month‐olds, we use a psychoacoustic approach to examine if and how degradation of the two fundamental acoustic components extracted from speech by the auditory system, namely, temporal (both frequency and amplitude modulation) and spectral information, impact word form segmentation. Infants were familiarized with passages containing target words, in which frequency modulation (FM) information was replaced with pure tones using a vocoder, while amplitude modulation (AM) was preserved in either 8 or 16 spectral bands. Infants were then tested on their recognition of the target versus novel control words. While the 6‐month‐olds were unable to segment in either condition, the 10‐month‐olds succeeded, although only in the 16 spectral band condition. These findings suggest that 6‐month‐olds need FM temporal cues for speech segmentation while 10‐month‐olds do not, although they need the AM cues to be presented in enough spectral bands (i.e., 16). This developmental change observed in infants' sensitivity to spectrotemporal cues likely results from an increase in the range of available segmentation procedures, and/or shift from a vowel to a consonant bias in lexical processing between the two ages, as vowels are more affected by our acoustic manipulations. Research Highlights: Although segmenting speech into word forms is crucial for lexical acquisition, the acoustic information that infants' auditory system extracts to process continuous speech remains unknown.We examined infants' sensitivity to spectrotemporal cues in speech segmentation using vocoded speech, and revealed a developmental change between 6 and 10 months of age.We showed that FM information, that is, the fast temporal modulations of speech, is necessary for 6‐ but not 10‐month‐old infants to segment word forms.Moreover, reducing the number of spectral bands impacts 10‐month‐olds' segmentation abilities, who succeed when 16 bands are preserved, but fail with 8 bands. [ABSTRACT FROM AUTHOR]

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

Introduction: Infants' sensitivity to language-specific phonotactic regularities emerges between 6- and 9- months of age, and this sensitivity has been shown to impact other early processes such as wordform segmentation and word learning. However, the acquisition of phonotactic regularities involving perceptually low-salient phonemes (i.e., phoneme contrasts that are hard to discriminate at an early age), has rarely been studied and prior results show mixed findings. Here, we aimed to further assess infants' acquisition of such regularities, by focusing on the low-salient contrast of /s/- and /ʃ/-initial consonant clusters. Methods: Using the headturn preference procedure, we assessed whether French- and German-learning 9-month-old infants are sensitive to languagespecific regularities varying in frequency within and between the two languages (i.e., /st/ and /sp/ frequent in French, but infrequent in German, /ʃt/ and /ʃp/ frequent in German, but infrequent in French). Results: French-learning infants preferred the frequent over the infrequent phonotactic regularities, but the results for the German-learning infants were less clear. Discussion: These results suggest crosslinguistic acquisition patterns, although an exploratory direct comparison of the French- and German-learning groups was inconclusive, possibly linked to low statistical power to detect such differences. Nevertheless, our findings suggest that infants' early phonotactic sensitivities extend to regularities involving perceptually low-salient phoneme contrasts at 9 months, and highlight the importance of conducting crosslinguistic research on such language-specific processes. [ABSTRACT FROM AUTHOR]

Introduction: The auditory system encodes the phonetic features of languages by processing spectro-temporal modulations in speech, which can be described at two time scales: relatively slow amplitude variations over time (AM, further distinguished into the slowest <8–16 Hz and faster components 16–500 Hz), and frequency modulations (FM, oscillating at higher rates about 600–10 kHz). While adults require only the slowest AM cues to identify and discriminate speech sounds, infants have been shown to also require faster AM cues (>8–16 Hz) for similar tasks. Methods: Using an observer-based psychophysical method, this study measured the ability of typical-hearing 6-month-olds, 10-month-olds, and adults to detect a change in the vowel or consonant features of consonant-vowel syllables when temporal modulations are selectively degraded. Two acoustically degraded conditions were designed, replacing FM cues with pure tones in 32 frequency bands, and then extracting AM cues in each frequency band with two dierent low-pass cut- o frequencies: (1) half the bandwidth (Fast AM condition), (2) <8 Hz (Slow AM condition). Results: In the Fast AM condition, results show that with reduced FM cues, 85% of 6-month-olds, 72.5% of 10-month-olds, and 100% of adults successfully categorize phonemes. Among participants who passed the Fast AM condition, 67% of 6-month-olds, 75% of 10-month-olds, and 95% of adults passed the Slow AM condition. Furthermore, across the three age groups, the proportion of participants able to detect phonetic category change did not dier between the vowel and consonant conditions. However, age-related dierences were observed for vowel categorization: while the 6- and 10-month-old groups did not dier from one another, they both independently diered from adults. Moreover, for consonant categorization, 10-month-olds were more impacted by acoustic temporal degradation compared to 6-month-olds, and showed a greater decline in detection success rates between the Fast AM and Slow AM conditions. Discussion: The degradation of FM and faster AM cues (>8 Hz) appears to strongly aect consonant processing at 10 months of age. These findings suggest that between 6 and 10 months, infants show dierent developmental trajectories in the perceptual weight of speech temporal acoustic cues for vowel and consonant processing, possibly linked to phonological attunement. [ABSTRACT FROM AUTHOR]

Many human infants grow up learning more than one language simultaneously but only recently has research started to study early language acquisition in this population more systematically. The paper gives an overview on findings on early language acquisition in bilingual infants during the first two years of life and compares these findings to current knowledge on early language acquisition in monolingual infants. Given the state of the research, the overview focuses on research on phonological and early lexical development in the first two years of life. We will show that the developmental trajectory of early language acquisition in these areas is very similar in mono- and bilingual infants suggesting that these early steps into language are guided by mechanisms that are rather robust against the differences in the conditions of language exposure that mono- and bilingual infants typically experience. [ABSTRACT FROM AUTHOR]

Infants start learning the prosodic properties of their native language before 12 months, as shown by the emergence of a trochaic bias in English-learning infants between 6 and 9 months (Jusczyk et al., 1993), and in German-learning infants between 4 and 6 months (Höhle et al., 2009, 2014), while French-learning infants do not show a bias at 6 months (Höhle et al., 2009). This language-specific emergence of a trochaic bias is supported by the fact that English and German are languages with trochaic predominance in their lexicons, while French is a language with phrase-final lengthening but lacking lexical stress. We explored the emergence of a trochaic bias in bilingual French/German infants, to study whether the developmental trajectory would be similar to monolingual infants and whether amount of relative exposure to the two languages has an impact on the emergence of the bias. Accordingly, we replicated Höhle et al. (2009) with 24 bilingual 6-month-olds learning French and German simultaneously. All infants had been exposed to both languages for 30 to 70% of the time from birth. Using the Head Preference Procedure, infants were presented with two lists of stimuli, one made up of several occurrences of the pseudoword /GAba/ with word-initial stress (trochaic pattern), the second one made up of several occurrences of the pseudoword /gaBA/ with word-final stress (iambic pattern). The stimuli were recorded by a native German female speaker. Results revealed that these French/German bilingual 6-montholds have a trochaic bias (as evidenced by a preference to listen to the trochaic pattern). Hence, their listening preference is comparable to that of monolingual German-learning 6-month-olds, but differs from that of monolingual French-learning 6-month-olds who did not show any preference (Höhle et al., 2009). Moreover, the size of the trochaic bias in the bilingual infants was not correlated with their amount of exposure to German. The present results thus establish that the development of a trochaic bias in simultaneous bilinguals is not delayed compared to monolingual German-learning infants (Höhle et al., 2009) and is rather independent of the amount of exposure to German relative to French. [ABSTRACT FROM AUTHOR]

Many studies have shown that during the first year of life infants start learning the prosodic, phonetic and phonotactic properties of their native language. In parallel, infants start associating sound sequences with semantic representations. However, the question of how these two processes interact remains largely unknown. The current study explores whether (and when) the relative phonotactic probability of a sound sequence in the native language has an impact on infants’ word learning. We exploit the fact that Labial-Coronal (LC) words are more frequent than Coronal-Labial (CL) words in French, and that French-learning infants prefer LC over CL sequences at 10 months of age, to explore the possibility that LC structures might be learned more easily and thus at an earlier age than CL structures. Eye movements of French-learning 14- and 16-month-olds were recorded while they watched animated cartoons in a word learning task. The experiment involved four trials testing LC sequences and four trials testing CL sequences. Our data reveal that 16-month-olds were able to learn the LC and CL words, while14-month-olds were only able to learn the LC words, which are the words with the more frequent phonotactic pattern. The present results provide evidence that infants’ knowledge of their native language phonotactic patterns influences their word learning: Words with a frequent phonotactic structure could be acquired at an earlier age than those with a lower probability. Developmental changes are discussed and integrated with previous findings. [ABSTRACT FROM AUTHOR]

Young deaf children using a cochlear implant develop speech abilities on the basis of speech temporal-envelope signals distributed over a limited number of frequency bands. A Headturn Preference Procedure was used to measure looking times in 6-month-old, normal-hearing infants during presentation of repeating or alternating sequences composed of different tokens of /aba/and /apa/ processed to retain envelope information below 64 Hz while degrading temporal fine structure cues. Infants attended longer to the alternating sequences, indicating that they perceive the voicing contrast on the basis of envelope cues alone in the absence of fine spectral and temporal structure information. [ABSTRACT FROM AUTHOR]

Two experiments explored 16-month-olds' learning of new nouns, and their use of these nouns to categorize objects. In both experiments, infants were presented with triads of perceptually dissimilar objects, which were given made-up names, two of the objects receiving the same name. Following each training phase, infants were tested on whether: (a) they could use the names to categorize the objects (Experiment 1), or (b) they had actually learned the association between the names and the objects (Experiment 2). Our results show that 16-month-olds can simultaneously learn the name of three objects, but cannot use these newly learned names to categorize the objects in the absence of any other cue to categorization. These results are discussed in light of different hypotheses regarding the way infants come to use names to categorize objects. [ABSTRACT FROM AUTHOR]

In the present paper, we address the issue of the emergence in infancy of speech segmentation procedures that were found to be specific to rhythmic classes of languages in adulthood. These metrical procedures, which segment fluent speech into its constitutive word sequence, are crucial for the acquisition by infants of the words of their native language. We first present a prosodic bootstrapping proposal according to which the acquisition of these metrical segmentation procedures would be based on an early sensitivity to rhythm (and rhythmic classes). We then review several series of experiments that have studied infants’ ability to discriminate languages between birth and 5 months, in an attempt to specify their sensitivity to rhythm and the implication of rhythm perception in the acquisition of these segmentation procedures. The results presented here establish infants’ sensitivity to rhythmic classes (from birth onwards). They further show an evolution of infants’ language discriminations between birth and 5 months which, though not inconsistent with our proposal, nevertheless call for more studies on the possible implication of rhythm in the acquisition of the metrical segmentation procedures. [Copyright &y& Elsevier]

Discusses the evolution of infants' language-discrimination abilities. Influence of the rhythm of one's native language on on-line speech processing; Language discrimination abilities of English-learning 5-month-olds babies; Infant's ability to discriminate between rhythmic classes; Infants' reliance on prosodic information to distinguish the native language.

Abstract: In order to acquire their native language, infants must learn to identify and segment word forms in continuous speech. This word segmentation ability is thus crucial for language acquisition. Previous behavioral studies have shown that it emerges during the first year of life, and that early segmentation differs according to the language in acquisition. In particular, linguistic rhythm, which differs across classes of languages, has been found to have an early impact on segmentation abilities. For French, behavioral evidence showed that infants could use the rhythmic unit appropriate to their native language (the syllable) to segment fluent speech by 12months of age, but failed to show whole word segmentation at that age, a surprising delay compared to the emergence of segmentation abilities in other languages. Given the implications of such findings, the present study reevaluates the issue of whole word and syllabic segmentation, using an electrophysiological method, high-density ERPs (event-related potentials), rather than a behavioral technique, and by testing French-learning 12-month-olds on bisyllabic word segmentation. The ERP data show evidence of whole word segmentation while also confirming that French-learning infants rely on syllables to segment fluent speech. They establish that segmentation and recognition of words/syllables happen within 500ms of their onset, and raise questions regarding the interaction between syllabic segmentation and multisyllabic word recognition. [Copyright &y& Elsevier]

French-learning infants have language-specific difficulties in processing lexical stress due to the lack of lexical stress in French. These difficulties in discriminating between words with stress-initial (trochaic) and stress-final (iambic) patterns emerge by 10 months of age in the easier context of low variability (using a single item pronounced with a trochaic pattern vs. an iambic pattern) as well as in the more challenging context of high segmental variability (using lists of segmentally different trochaic and iambic items). These findings raise the question of stress pattern perception in simultaneous bilinguals learning French and a second language using stress at the lexical level. Bijeljac-Babic, Serres, Höhle, and Nazzi (2012) established that at 10 months of age, in the simpler context of low variability, such bilinguals have better stress discrimination abilities than French-learning monolinguals. The current study explored whether this advantage extends to the more challenging context of high segmental variability. Results first establish stress pattern discrimination in a group of bilingual 10-month-olds learning French and one language with (variable) lexical stress, but not in French-learning 10-month-old monolinguals. Second, discrimination in bilinguals appeared not to be affected by the language balance of the infants, suggesting that sensitivity to stress patterns might be maintained in these bilingual infants provided that they hear at least 30% of a language with lexical stress. [ABSTRACT FROM AUTHOR]

Previous studies have described the existence of a phonotactic bias called the Labial-Coronal (LC) bias, corresponding to a tendency to produce more words beginning with a labial consonant followed by a coronal consonant (i.e. "bat") than the opposite CL pattern (i.e. "tap"). This bias has initially been interpreted in terms of articulatory constraints of the human speech production system. However, more recently, it has been suggested that this presumably language-general LC bias in production might be accompanied by LC and CL biases in perception, acquired in infancy on the basis of the properties of the linguistic input. The present study investigates the origins of these perceptual biases, testing infants learning Japanese, a language that has been claimed to possess more CL than LC sequences, and comparing them with infants learning French, a language showing a clear LC bias in its lexicon. First, a corpus analysis of Japanese IDS and ADS revealed the existence of an overall LC bias, except for plosive sequences in ADS, which show a CL bias across counts. Second, speech preference experiments showed a perceptual preference for CL over LC plosive sequences (all recorded by a Japanese speaker) in 13- but not in 7- and 10-month-old Japanese-learning infants (Experiment 1), while revealing the emergence of an LC preference between 7 and 10 months in French-learning infants, using the exact same stimuli. These crosslinguistic behavioral differences, obtained with the same stimuli, thus reflect differences in processing in two populations of infants, which can be linked to differences in the properties of the lexicons of their respective native languages. These findings establish that the emergence of a CL/LC bias is related to exposure to a linguistic input. [ABSTRACT FROM AUTHOR]