Processing of lexical stress cues by young children.

Although infants learn an impressive amount about their native-language phonological system by the end of the first year of life, after the first year children still have much to learn about how acoustic dimensions cue linguistic categories in fluent speech. The current study investigated what children have learned about how the acoustic dimension of pitch indicates the location of the stressed syllable in familiar words. Preschoolers (2.5- to 5-year-olds) and adults were tested on their ability to use lexical-stress cues to identify familiar words. Both age groups saw pictures of a bunny and a banana and heard versions of "bunny" and "banana" in which stress either was indicated normally with convergent cues (pitch, duration, amplitude, and vowel quality) or was manipulated such that only pitch differentiated the words' initial syllables. Adults (n=48) used both the convergent cues and the isolated pitch cue to identify the target words as they unfolded. Children (n=206) used the convergent stress cues but not pitch alone in identifying words. We discuss potential reasons for children's difficulty in exploiting isolated pitch cues to stress despite children's early sensitivity to pitch in language. These findings contribute to a view in which phonological development progresses toward the adult state well past infancy.