Effects of speech rate on tongue kinematics during production of Cantonese plosives

Abstract

PURPOSE: Previous research revealed that articulators performed differently when speaking rate is altered. Yet, little is known about the physiological basis of tongue movement changes under different speech rate conditions. The aim of the present study was to investigate the effects of speech rate on tongue kinematics during production of Cantonese plosives. METHODS: Electromagnetic articulography was used to record tongue tip and tongue dorsum movement during production of alveolar and velar plosives by twenty adult native speakers of Cantonese. The selected aspirated and unaspirated plosives (/th/, /t/,/ kh/and/k/) were produced at three speech rates, i.e. slow (one syllable per second), normal (three syllables per second) and fast (as fast as possible). RESULTS: Results showed that the range of tongue tip and tongue dorsum movement consistently decreased with increasing speech rate during aspirated and unaspirated plosives production. Greater tongue tip movement velocity was documented at normal speech rate when compared with slow and fast speech rates, evidenced in both aspirated and unaspirated alveolar plosives production. However, tongue dorsum movement velocity during aspirated and unaspirated velar plosives production showed a trend of increment with speech rate. Differential interaction between aspiration and speech rate was also revealed. CONCLUSION: Inconsistent effects of speech rate on tongue tip and tongue dorsum movement kinematics during Cantonese plosives production were documented. These findings suggest that Cantonese speakers utilized a combination of range reduction and velocity increment strategies of tongue movement in speech production at different speech rates.