The effect of speaking style alterations on locus equation stability

Abstract

Locus equations, as a phonetic descriptor of stop place of production, have been systematically investigated across speakers, gender, languages, perturbation conditions, syllable position, and manner class. As locus equation slope is thought to directly reflect the extent of anticipatory coarticulation of the vowel on the prevocalic consonant, changes in coarticulation as brought about by altered speaking styles can effectively alter locus equation descriptors of stop place. This study attempted to assess the stability of locus equations within each speaker as citation-style hyperarticulation was compared relative to spontaneous, hypoarticulated output. Twenty speakers, ten male and ten female served as subjects. Traditional citation-style locus equations were generated from productions of CV /t/ words printed on lists with initial /bdg/ followed by ten medial vowel contexts. Locus equations were also derived from spontaneous speech output which was generated by rapid reading of discourse-like passages constructed to resemble normal conversational speech, but with numerous lexical items beginning with /bdg/ in many vowel contexts. Spectral analysis was performed with the Kay Elemetrics CSL system. Comparisons of slopes, y intercepts, R2, and standard error of estimates across the two speaking conditions will be presented and discussed.