The Sequential Development of Jaw and Lip Control for Speech Vertical displacements of the upper lip, lower lip, and jaw during speech were recorded for groups of 1-, 2-, and 6-year-olds and adults to examine if control over these articulators develops sequentially. All movement traces were amplitudeand time-normalized. The developmental course of upper lip, lower lip, and jaw control was ... Research Article
Research Article  |   February 01, 2002
The Sequential Development of Jaw and Lip Control for Speech
 
Author Affiliations & Notes
  • Jordan R. Green, PhD
    Department of Communicative Disorders University of Wisconsin-Madison
  • Christopher A. Moore
    Department of Speech and Hearing Sciences University of Washington Seattle
  • Kevin J. Reilly
    Department of Speech and Hearing Sciences University of Washington Seattle
  • Contact author: Jordan R. Green, PhD, Department of Communicative Disorders, University of Wisconsin-Madison, 1975 Willow Drive, Madison, WI 53706. E-mail: jordangreen@fac,staff.wisc.edu
Article Information
Development / Speech, Voice & Prosodic Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 2002
The Sequential Development of Jaw and Lip Control for Speech
Journal of Speech, Language, and Hearing Research, February 2002, Vol. 45, 66-79. doi:10.1044/1092-4388(2002/005)
History: Received May 7, 2001 , Accepted October 31, 2001
 
Journal of Speech, Language, and Hearing Research, February 2002, Vol. 45, 66-79. doi:10.1044/1092-4388(2002/005)
History: Received May 7, 2001; Accepted October 31, 2001
Web of Science® Times Cited: 111

Vertical displacements of the upper lip, lower lip, and jaw during speech were recorded for groups of 1-, 2-, and 6-year-olds and adults to examine if control over these articulators develops sequentially. All movement traces were amplitudeand time-normalized. The developmental course of upper lip, lower lip, and jaw control was examined by quantifying age-related changes in the similarity of each articulator's movement patterns to those produced by adult subjects and by same-age peers. In addition, differences in token-to-token stability of articulatory movement were assessed among the different age groups. The experimental findings revealed that 1- and 2-year-old children's jaw movements were significantly more adult-like than their upper and lower lip movements, which were more variable. In contrast, upper and lower lip movement patterns became more adult-like with maturation. These findings suggest that the earliest stages of speech motor development are constrained by the nonuniform development of articulatory control, with the jaw preceding the lips. The observed developmental patterns suggest that the properties of the oral motor control system significantly influence the pattern of speech sound acquisition.

Acknowledgments
This research was supported in part by research grants (R01 DC00822 and R03 DC4643-01) from the National Institute on Deafness and Other Communication Disorders. The authors would like to thank Anne Smith for providing example interpolation routines and Gary Weismer and Ray Kent for helpful feedback on earlier versions of this manuscript.
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