A kinematic analysis of speech sound production in children and adults

Lisa Alice Goffman, Purdue University

Abstract

Along with perceptual and cognitive-linguistic factors, motor mechanisms are thought to influence the development of speech and language. In the present investigation, features of movement were examined across three developmental periods, in 4-year-old and 7-year-old children and adults. The goals were as follows: (1) to determine the nature of basic features (i.e., displacement, velocity, duration) and underlying patterns of movement and the variability of these features and patterns; (2) to determine how the production of specific consonants is reflected in movement features and patterns. Lower lip movement was recorded while speakers produced words containing labial phonetic contrasts (i.e., man, pan, ban, fan, and van). Findings could be divided into two major categories. First, children and adults were observed to produce qualitatively different features and patterns of movement. Young children produce smaller and slower movements than adults. The variability of movement diminishes across developmental periods. Also, the organization of movement changes. Four-year-old children produce more submovements than 7-year-olds. These submovements are unsystematic and disorganized. Seven-year-old children, on the other hand, produce very simple close-open sequences, with few submovements added. Adults, like 4-year-old children, include submovements in their sequences, but these are systematic and linked to phonetic context. Across age groups, both individual features and overall patterns of movement contribute to phonetic differentiation. Duration, displacement, and underlying patterning of movement all are significantly influenced by word context. Therefore, although properties of movement differ dramatically across age groups, no age effects are observed in degree of phonetic specificity.

Degree

Ph.D.

Advisors

Smith, Purdue University.

Subject Area

Speech therapy

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