Electropalatographic and acoustic measures of adaptation to palatal perturbation

Abstract

The present investigation examined adaptation to a palatal perturbation in [s] production, as reflected in both electropalatographic (EPG) and acoustic measures. The goal was to explore the development of compensatory motor programs during the production of individual fricative segments, as well as over a 1-h period of focused practice. Thirty repetitions of the syllable [sa] were produced at each of five time intervals (times 0, 15, 30, 45, and 60 min) by a speaker wearing a specially designed pseudopalate with a 6 mm buildup of acrylic at the alveolar ridge. At times 0 and 60, baseline measures of [sa] production with a thin pseudopalate and with no palate in place were also recorded to characterize unperturbed articulation. Acoustic analyses focused on centroid frequencies for the [s] productions, while a wide range of EPG analyses were conducted including measures of groove length and width, location and duration of maximum constriction, and variability in tongue-palate contact patterns throughout the fricative production. Preliminary analyses indicate a high degree of variability throughout the practice period. Results are discussed in relation to the development of adaptive articulatory programs in speech motor control and the articulatory configurations necessary for adequate [s] production. [Work supported by NSERC.]