How the prosodic cues in motherese might assist language learning.

The function of motherese has become a pivotal issue in the language-learning literature. The current research takes the approach of asking whether the prosodic characteristics that are distinctive to motherese could play a special role in facilitating the acquisition of syntax. Hirsh-Pasek, Kemler Nelson, Jusczyk, Cassidy, Druss & Kennedy (1987) showed that infants aged 0;7-0;10 are sensitive to prosodic cues that would help them segment the speech stream into perceptual units that correspond to clauses. The present study shows that infants' sensitivity to segment-marking cues in ongoing speech holds for motherese but not for adult-directed speech. The finding is that, for motherese only, infants orient longer to speech that has been interrupted at clausal boundaries than to matched speech that has been interrupted at within-clause locations. This selective preference indicates that the prosodic qualities of motherese provide infants with cues to units of speech that correspond to grammatical units of language-a potentially fundamental contribution of motherese to the learning of syntax.