Kinematic analysis of labial and mandibular movements during production of Cantonese bilabial plosives

Abstract

The present study examined the possible effects of aspiration and vowel context on labial and mandibular movements during production of Cantonese bilabial plosives /p/ and /ph/. The movements of upper lip, lower lip, and lower jaw associated with the speech samples produced by 30 adult native Cantonese speakers were recorded using a three-dimensional electromagnetic articulography (Carstens Medizinelektronik GmbH, AG500 EMA). Participants were instructed to produce VCV sequences arranged in a random order. Kinematic analysis of labial and mandibular movements during the burst release phase of bilabial plosives revealed a significant aspiration effect on the vertical displacement and velocity of lower jaw, and such effect was consistent across all vowel contexts. Similarly, a significant aspiration effect was observed in the vertical displacement of lower lip. However, results did not reveal any significant aspiration effect on the anteroposterior displacement and velocity in both upper and lower lip movements, despite some effects of vowel context were observed. The findings appear to confirm the hypothesis of muscular force as the main driving force in facilitating the production of unaspirated bilabial plosive /p/. Yet, the mechanism governing the lip/jaw opening for aspirated cognate /ph/ may require further examination.