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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.

A surprising comprehension-production asymmetry in subject-verb (SV) agreement acquisition has been suggested in the literature, and recent research indicates that task-specific as well as language-specific features may contribute to this apparent asymmetry across languages. The present study investigates when during development children acquiring Mexican Spanish gain competence with 3rd-person SV agreement, testing production as well as comprehension in the same children aged between 3;6 and 5;7 years, and whether comprehension of SV agreement is modulated by the sentential position of the verb (i.e., medial vs. final position). Accuracy and sensitivity analyses show that comprehension performance correlates with SV agreement production abilities, and that comprehension of singular and plural third-person forms is not influenced by the sentential position of the agreement morpheme. Issues of the appropriate outcome measure and the role of structural familiarity in the development of abstract representations are discussed.

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.

We examined French-learning toddlers' sensitivity to Subject-Verb agreement with conjoined subjects. In French, a conjoined NP triggers plural agreement even when made up of individual singular NPs. Processing of this infrequent structure in the input (see Corpus Analyses) requires going beyond surface patterns of non-adjacent dependencies to abstract, feature-based syntactic knowledge. In Experiment 1, results revealed a significant grammaticality effect in 24-month-olds, but not in 18-month-olds, with no interaction with the condition (with either conjoined or non-conjoined agreement; all tested with Head-Turn Preference Procedure). In Experiment 2, 30-month-olds (tested with conjoined agreement only) showed the same pattern as 24-month-olds: a strong grammaticality effect limited to the first half of the experiment. Overall, these results provide some support to the hypothesis that 24- and 30-month-olds (but not 18-month-olds) have abstract knowledge of SV agreement with conjoined subjects, although it imposes a high processing cost. Importantly, this abstract syntactic sensitivity precedes the earliest evidence of simple agreement comprehension.

Perceptual grouping is fundamental to many auditory processes. The Iambic-Trochaic Law (ITL) is a default grouping strategy, where rhythmic alternations of duration are perceived iambically (weak-strong), while alternations of intensity are perceived trochaically (strong-weak). Some argue that the ITL is experience dependent. For instance, French speakers follow the ITL, but not as consistently as German speakers. We hypothesized that learning about prosodic patterns, like word stress, modulates this rhythmic grouping. We tested this idea by training French adults on a German-like stress contrast. Individuals who showed better phonological learning had more ITL-like grouping, particularly over duration cues. In a non-phonological condition, French adults were trained using identical stimuli, but they learned to attend to acoustic variation that was not linguistic. Here, no learning effects were observed. Results thus suggest that phonological learning can modulate low-level auditory grouping phenomena, but it is constrained by the ability of individuals to learn from short-term training.

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 present study applies a multidimensional methodological approach to the study of the acquisition of morphosyntax. It focuses on evaluating the degree of productivity of an infrequent subject-verb agreement pattern in the early acquisition of French and considers the explanatory role played by factors such as input frequency, semantic transparency of the agreement markers, and perceptual factors in accounting for comprehension of agreement in number (singular vs. plural) in an experimental setting. Results on a pointing task involving pseudoverbs demonstrate significant comprehension of both singular and plural agreement in children aged 2;6. The experimental results are shown not to reflect input frequency, input marker reliability on its own, or lexically driven knowledge. We conclude that toddlers have knowledge of subject-verb agreement at age 2;6 which is abstract and productive despite its paucity in the input.

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.)

The present study explores phonetic processing in deaf children with cochlear implants (CIs) when they have to learn phonetically similar words. Forty-six 34-to-78-month-old French-speaking deaf children with CIs were tested on 16 different trials. In each trial, they were first trained with two word-object pairings, and then a third object was presented and labeled with one of the familiar words. Children were asked to match one of the previously labeled objects with the third (same-labeled) object. Each pair of words contrasted on either the initial consonant or the first vowel by one or several phonetic features. The results show that deaf children with CIs are able to establish a new referential link between a word and an object. However, their performance is lower than that previously observed in normal-hearing children (NH). In such a situation, they process contrasts involving several phonetic features correctly, but show difficulties with minimal contrasts. The ability to recruit fine phonetic sensitivity during word learning appears to be influenced mainly by duration of implant use, with an overall increase of performance during the 3 years after implantation. There was no chronological age effect, nor age at implantation effect on the quality of processing. Difficulty with minimal contrasts and the absence of any age at implantation effects in this age range are discussed in light of recent studies on lexical development. Learning outcomes: After reading this article, the reader will be able to recognize the perceptual skills of children with cochlear implants and distinguish those perceptual features that are difficult for the children to perceive. (Contains 2 tables and 2 figures.)

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.

Consonants and vowels have been shown to play different relative roles in different processes, including retrieving known words from pseudowords during adulthood or simultaneously learning two phonetically similar pseudowords during infancy or toddlerhood. The current study explores the extent to which French-speaking 3- to 5-year-olds exhibit a so-called "consonant bias" in a task simulating word acquisition, that is, when learning new words for unfamiliar objects. In Experiment 1, the to-be-learned words differed both by a consonant and a vowel (e.g., /byf/-/duf/), and children needed to choose which of the two objects to associate with a third one whose name differed from both objects by either a consonant or a vowel (e.g., /dyf/). In such a conflict condition, children needed to favor (or neglect) either consonant information or vowel information. The results show that only 3-year-olds preferentially chose the consonant identity, thereby neglecting the vowel change. The older children (and adults) did not exhibit any response bias. In Experiment 2, children needed to pick up one of two objects whose names differed on either consonant information or vowel information. Whereas 3-year-olds performed better with pairs of pseudowords contrasting on consonants, the pattern of asymmetry was reversed in 4-year-olds, and 5-year-olds did not exhibit any significant response bias. Interestingly, girls showed overall better performance and exhibited earlier changes in performance than boys. The changes in consonant/vowel asymmetry in preschoolers are discussed in relation with developments in linguistic (lexical and morphosyntactic) and cognitive processing. (Contains 3 figures and 6 tables.)

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)