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An age-related increase in the fricative contrast /s/-/ʃ/, measured acoustically, occurs in children up to 7 years of age, with 5- and 7-year-olds producing contrasts that are greater than those of younger children, but still significantly smaller than the contrasts produced by adults. Kinematic studies have demonstrated that adult-like speech motor control does not emerge until later adolescence, although no articulatory studies of sibilant production in later childhood have been reported. In this study, the aim was to understand the relative use of somatosensory and acoustic/auditory goals for the production of the fricative contrast in older children (10–15 years of age) and adults. The fricative contrast was measured in the acoustic signal and in articulatory data gathered from the tongue blade. The acoustic and articulatory contrasts were analyzed to test the magnitude of the covariation of the two domains. We further analyzed the development of the contrast in both domains as a function of later speech development. Results will be discussed in the context of the hypothesis that sibilants are produced with prominent goals in both the somatosensory and auditory domains but that auditory goals predominate in older children because of continued refinement of feedforward commands.

A previous report described significant differences between males and females in the shape of the tongue during the production of vowels (Vick et al., 2014). The purpose of the present study was to understand the influence of palate morphology on these measured differences in tongue shape. This study examined tongue movements in consonant-vowel-consonant sequences drawn from words in phrases as produced by 32 participants, including 12 adults (6m, 6f) and 20 children (2m and 2f at each age of 11, 12, 13, 14, and 15 years). Movements of four points on the tongue were tracked at 100 Hz using the Wave Electromagnetic Speech Research System (NDI, Waterloo, ON, CA). Palate curvature measures were derived from a hard palate trace made with a 6dof probe sensor. The phrases produced included the vowels /i/, /I/, /ae/, and /u/ in words (i.e., “see,” sit,” cat,” and “zoo”). The horizontal curvature of the tongue was calculated at the trajectory speed minimum associated with the vowel production using a least-squares...

This study examined tongue movements in consonant-vowel-consonant sequences drawn from real words in phrases as produced by 36 older children (three male and three female talkers at each age from 10 to 15 years) and 36 adults. Movements of four points on the tongue were tracked at 400 Hz using the Wave Electromagnetic Speech Research System (NDI, Waterloo, ON, CA). The four points were tongue tip (TT; 1 cm from tip on midline), tongue body (TB; 3 cm from tip on midline), tongue right (TR; 2 cm from tip on right lateral edge), and tongue left (TR; 2 cm from tip on left lateral edge). The phrases produced included the vowels /i/, /I/, /ae/, and /u/ in words (i.e., “see,” sit,” cat,” and “zoo”). Movement measures included 3D distance, peak and average speed, and duration of vowel opening and closing strokes. The horizontal curvature of the tongue was calculated at the trajectory speed minimum associated with the vowel production using a least-squares quadratic fit of the TR, TB, and TL positional coordinates...