Department of Special Education and Communication Disorders

 

Date of this Version

2-2000

Comments

Published in Journal of Speech, Language & Hearing Research 43:1 (February 2000), pp. 239–255. Copyright © American Speech-Language-Hearing Association. Used by permission.

Abstract

This investigation was designed to describe the development of lip and jaw coordination during speech and to evaluate the potential influence of speech motor development on phonologic development. Productions of syllables containing bilabial consonants were observed from speakers in four age groups (i.e., 1-year-olds, 2-year-olds, 6-year-olds, and young adults). A video-based movement tracking system was used to transduce movement of the upper lip, lower lip, and jaw. The coordinative organization of these articulatory gestures was shown to change dramatically during the first several years of life and to continue to undergo refinement past age 6. The present results are consistent with three primary phases in the development of lip and jaw coordination for speech: integration, differentiation, and refinement. Each of these developmental processes entails the existence of distinct coordinative constraints on early articulatory movement. It is suggested that these constraints will have predictable consequences for the sequence of phonologic development.

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