The development of phonological categories in children's perception of final voicing in dialects of English
This dissertation addresses the general question of how children's phonological categories in perception differ from adults' phonological categories. A well-known characteristic of adults' phonological categories is the existence of trading relations and integration among cues to a phonological category. In trading relations, less evidence from one cue to a phonological category can be offset by more evidence from another cue. When cues are integrated by the listener, the cues are not used independently; instead the perceptual value of one cue depends on the value of another. Little research has previously been carried out into the development of trading relations and integration in children's speech perception. This dissertation tests two possible factors affecting the development of adultlike trading relations: the distribution of cues in the dialect or language variety being learned, and the development of integration. The results of identification experiments with adult and four- to six-year-old child listeners from different dialects (Standard American English, African American English, and Australian English) suggest that children's trading relations develop to approximate those of the adults in their dialect group. Children's trading relations differ, however, in that children make relatively heavier use of one cue to a contrast. The results of a discrimination experiment suggest that integration of vowel duration and first formant (F1) cues to final stop voicing in Australian English develop gradually in childhood. The implications of this finding are discussed with respect to gesturalist, auditorist, and associative views of trading relations. The finding suggests that whether or not integration for some trading relations results from the recovery of a gesture or the experience of an auditory property, integration for some subtypes of trading relations, such as context effects, may develop as a result of learning from experience with patterns of acoustic covariation among cues to phonological categories.
0633: Cognitive therapy
0620: Developmental psychology