Segmental and syllabic representations in the perception of speech by young infants

In a series of four experiments, the ability of 3- to 4-month-old infants to form categorical representations to syllable-initial consonants in monosyllabic stimuli (experiments 1 and 2) and to initial and final syllables in bisyllabic stimuli (experiments 3 and 4, respectively) was investigated. Experiment 1 yielded no evidence of categorical representations for the initial consonant. However, the results indicated that the four or six stimuli presented during the initial phase of familiarization had been remembered. The results of experiment 2? which employed a less stringent familiarization criterion, replicated the findings of experiment 1, although there was some evidence for categorization for infants whose familiarization performance more closely matched the weaker criterion. In experiment 3, there was strong evidence for a categorical representation of the initial syllable of bisyllabic stimuli for infants experiencing six familiar stimuli. In experiment 4, there was less robust evidence of categorization of the final syllable of bisyllabic stimuli, but again only when six familiar stimuli were experienced. The results were discussed in terms of the earliest representation of speech being syllables that could be modified by the rhythmic nature of the infant's native language. (C) 1999 Acoustical Society of America. [S0001-4966(99)01203-5].