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Infants make their first contacts with their native language through its sound patterns. Research over the past twenty years has demonstrated that infants are well-equipped to perceive subtle distinctions in speech sounds and to cope with the variability that is present in the speech signal. At the same time, it is clear that in order to progress in acquiring a language, infants need to learn about the particular characteristics of the sounds and combinations of sounds that are used in their native language. Recent findings suggest that the time between 6 and 9 months of age may be a particularly fertile one for learning about the sound patterns of one's native language. There are indications that infants are developing sensitivity to distributional properties of sounds in the input at this time. The implications of these findings have for our understanding of processes underlying language acquisition will be considered.

Comprehending spoken words requires a lexicon of sound patterns and knowledge of their referents in the world. Tincoff and Jusczyk (1999) demonstrated that 6-month-olds link the sound patterns "Mommy" and "Daddy" to video images of their parents, but not to other adults. This finding suggests that comprehension emerges at this young age and might take the form of very specific word-world links, as in "Mommy" referring only to the infant's mother and "Daddy" referring only to the infant's father. The current study was designed to investigate if 6-month-olds also show evidence of comprehending words that can refer to categories of objects. The results show that 6-month-olds link the sound patterns "hand" and "feet" to videos of an adult's hand and feet. This finding suggests that very early comprehension has a capacity beyond specific, one-to-one, associations. Future research will need to consider how developing categorization abilities, social experiences, and parent word use influence the beginnings of word comprehension.

The Possible Word Constraint limits the number of lexical candidates considered in speech recognition by stipulating that input should be parsed into a string of lexically viable chunks. For instance, an isolated single consonant is not a feasible word candidate. Any segmentation containing such a chunk is disfavored. Five experiments using the head-turn preference procedure investigated whether, like adults, 12-month-olds observe this constraint in word recognition. In Experiments 1 and 2, infants were familiarized with target words (e.g., "rush"), then tested on lists of nonsense items containing these words in "possible" (e.g., "niprush" [nip + rush]) or "impossible" positions (e.g., "prush" [p + rush]). The infants listened significantly longer to targets in "possible" versus "impossible" contexts when targets occurred at the end of nonsense items ("rush" in "prush"), but not when they occurred at the beginning ("tan" in "tance"). In Experiments 3 and 4, 12-month-olds were similarly familiarized with target words, but test items were real words in sentential contexts ("win" in "wind" versus "window"). The infants listened significantly longer to words in the "possible" condition regardless of target location. Experiment 5 with targets at the beginning of isolated real words (e.g., "win" in "wind") replicated Experiment 2 in showing no evidence of viability effects in beginning position. Taken together, the findings suggest that, in situations in which 12-month-olds are required to rely on their word segmentation abilities, they give evidence of observing lexical viability constraints in the way that they parse fluent speech.

Investigates whether English learners give evidence of observing markedness and faithfulness constraints relating to nasal place assimilation. Employs the Headturn Preference Procedure to introduce a general experimental paradigm for exploring infants phonological grammars. (Author/VWL)

This study investigated whether 9-month-olds used phonotactic cues to segment words from fluent speech. Results suggested that 9-month-olds use probabilistic phonotactics to segment speech into words, and that high- probability between-word clusters are interpreted as both word onsets and word offsets. (Author/KB)

Explored English-learning infants' capacities to segment bisyllabic words from fluent speech in a series of 15 experiments. Findings suggest that English learners may rely heavily on stress cues when they begin to segment words from fluent speech, but within a few months, infants learn to integrate multiple sources of information about word boundaries. (SLD)

This study compared role of motion in adults' and infants' perception of object unity. Findings favored ecologically-oriented accounts of object perception. Motion was a determinant of object unity for infants. Alignment and common motion contributed to adults' object-unity perception; synchronous color changes did not. Infants detected synchronous changes, but failed to use them as information for object unity. (Author/KB)

Examined speech segmentation in 9-month-old infants, studying phonotactic regularity and prosodic pattern in four experiments involving 96 infants. Discusses implications of the results in light of an integrated multiple-cue approach to speech segmentation in infancy. Contains 92 references. (SLD)

Five experiments examined 15- and 18-month olds' sensitivity to morphosyntactic dependencies. Results indicated that 18-month olds, but not 15-month olds, were sensitive to basic relationship between "is" and "-ing" and that 18-month-olds could track relationships between functor morphemes. Findings were consistent with hypothesis that 18-month olds work with a limited processing window and that they pick up relevant dependencies falling within this window. (Author/KB)

Six experiments involving 192 infants and 1 experiment with 16 college students examined sensitivity to acoustic correlates of phrasal units in English. A basic finding is that nine-month-old infants are sensitive to acoustic markers that correspond to major phrasal units, a sensitivity that develops after six months. (SLD)

Two studies examined relationships between infants' early speech processing performance and later language and cognitive outcomes. Study 1 found that performance on speech segmentation tasks before 12 months of age related to expressive vocabulary at 24 months. However, performance on other tasks was not related to 2-year vocabulary. Study 2 assessed linguistic and cognitive skills at 4-6 years of age for children who had participated in segmentation studies as infants. Children who had been able to segment words from fluent speech scored higher on language measures, but not general IQ, as preschoolers. Results suggest that speech segmentation ability is an important prerequisite for successful language development, and they offer potential for developing measures to detect language impairment at an earlier age. Keywords: speech segmentation, language development, outcomes, infant, individual differences

Abstract 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 [...]

Infants' long-term memory for the phonological patterns of words versus the indexical properties of talkers' voices was examined in 3 experiments using the Headturn Preference Procedure (D. G. Kemler Nelson et al., 1995). Infants were familiarized with repetitions of 2 words and tested on the next day for their orientation times to 4 passages--2 of which included the familiarized words. At 7.5 months of age, infants oriented longer to passages containing familiarized words when these were produced by the original talker. At 7.5 and 10.5 months of age, infants did not recognize words in passages produced by a novel female talker. In contrast, 7.5-month-olds demonstrated word recognition in both talker conditions when presented with passages produced by both the original and the novel talker. The findings suggest that talker-specific information can prime infants' memory for words and facilitate word recognition across talkers.

Speech cues were given more weight than statistical cues by 8-month-old infants in a series of experiments on word segmentation. Prosodic stress cues and coarticulation were the speech cues pitted against statistical cues; familiarity effects were also examined.

The study to examine whether 4.5-month-olds like to hear their own names over foils that were either similar or dissimilar in stress pattern showed that the young infants identify the sound patterns of their own names. Infants prefer their names in comparison to the foils that have the same stress patterns as well as foils with reverse patterns. The findings suggest that very young infants already start to identify sound patterns usually spoken in the infant's environments.

This study examined 2- to 3-month-olds' representations of bisyllables. In 3 experiments, infants were familiarized with sets of bisyllables that either did or did not share a common consonant-vowel (CV) syllable. In Experiment 1, infants detected the presence of a new bisyllable in the test phase except when it shared a common initial CV syllable. A modified version of the high-amplitude sucking (HAS) procedure, incorporating a 2-min delay period, tested infants' retention of information about bisyllables in the remaining 2 experiments. In Experiment 2, infants were significantly more likely to retain information about bisyllables that shared the same initial CV syllable. Finally, the authors investigated whether infants simply benefited from the presence of 2 common phonetic segments, regardless of whether these came from the same CV syllable. The results showed that CV syllable organization is important in infants' ability to encode and retain information about bisyllables.

The present studies were undertaken to learn more about the nature of the cues that underlie infants' perception of musical phrase structure. Experiment 1 demonstrated that infants in Krumhansl and Jusczyk's (1990) study were responding to the phrase structure instead of to the beginnings and endings of Mozart minuet stimuli. Experiment 2 showed that infants treat musical passages with pauses inserted at phrase boundaries much as they do unaltered versions of the same passages. Experiments 3 and 4 indicated that the direction of change in pitch height and tone duration is critical to obtaining longer orientation times to musical passages that are segmented at phrase boundaries. Finally, Experiment 5 demonstrates that different effects found for the forward and reversed versions of the passages with inserted pauses are not the result of an intrinsic preference for the forward versions.

Investigates the perceptual representation of speech by young infants using a modification of the high-amplitude sucking (HAS) procedure. Results demonstrate that the infants' representations preserve detailed information about both the consonantal and vocalic portions of the syllables. (Author/RWB)