Effects of aspiration and vowel context on lip and jaw kinematics in Cantonese bilabial plosive production

The present study examined the possible effects of aspiration and vowel context on lip and jaw movements during production of Cantonese bilabial plosives /p/ and /ph/. VCV syllables were randomly produced by 30 adult native Cantonese speakers. Movement of upper lip, lower lip, and jaw during speech production was recorded using an electromagnetic articulography (EMA). Kinematic analysis of lip and jaw movements during the opening phase of bilabial plosive production revealed a significant aspiration effect, especially on the vertical displacement and velocity of jaw. Such effect was consistent across all vowel contexts. Similarly, a significant aspiration effect was observed in the vertical displacement of lower lip. These findings suggest that muscular force is the main driving force in the production of unaspirated bilabial plosive /p/