Phonotactic cues for segmentation of fluent speech by infants

There is growing evidence that infants become sensitive to the probabilistic phonotactics of their ambient language sometime during the second half of their first year. The present study investigates whether 9-month-olds make use of phonotactic cues to segment words from fluent speech. Using the Headturn Preference Procedure, we found that infants listened to a CVC stimulus longer when the stimulus previously appeared in a sentential context with good phonotactic cues than when it appeared in one without such cues. The goodness of the phonotactic cues was estimated from the frequency with which the (C.C) under bar clusters at the onset and offset of a CVC test stimulus (i.e. (C.C) under barV (C.C) under bar) are found within and between words in child-directed speech, with high between-word probability associated with good cues to word boundaries. A similar segmentation result emerged when good phonotactic cues occurred only at the onset (i.e. (C.C) under bar VC.C) or the offset (i.e, C.CV (C.C) under bar) of the target words in the utterances. Together, the results suggest 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. (C) 2001 Elsevier Science B.V. All rights reserved.