INFANTS SENSITIVITY TO WORD BOUNDARIES IN FLUENT SPEECH

Infants' sensitivity to word units in fluent speech was examined by in serting I sec pauses either at boundaries between successive words (Co incident versions) or between syllables within words (Noncoincident ve rsions). In Experiment I, 24 II-month-olds listened significantly long er to the Coincident versions. In Experiment 2, 24 four-and-a-half-and 24 nine-month-olds did not exhibit the preference for the Coincident versions that the II-month-olds showed. When the stimuli were low-pass filtered in Experiment 3, 24 II-month-olds showed no preference for t he Coincident versions, suggesting they rely on more than prosodic cue s. New stimulus materials in Experiment 4 indicated that responses by 24 II-month-olds to the Coincident and Noncoindent versions did not de pend solely on prior familiarity with the targets. Two groups of 30 II -month-olds tested in Experiment 5 were as sensitive to boundaries for Strong/Weak words as for Weak/Strong words. Taken together, the resul ts suggest that, by II months, infants are sensitive to word boundarie s in fluent speech, and that this sensitivity depends on more than jus t prosodic information or prior knowledge of the words.