Differences in speech motor control between bilingual and monolingual speakers—An acoustic study

Abstract

The present study attempted to acoustically examine the speech motor abilities associated with English produced by English monolingual speakers (MS), Cantonese-English bilingual speakers with superior (BS-SE) and inferior English (BS-IE). Articulation rate, formant frequencies (F1 and F2), and voice onset time (VOT) obtained from different speech tasks were compared across the three speaker groups to reveal the language influence on their speech motor control. Results indicated that: (1) the MS group exhibited the fastest articulation rate while the BS-IE group the slowest; (2) the three speaker groups had significantly different VOT values for the plosives /b-/, /g-/, /ph-/ and /th-/; and (3) bilingual speakers exhibited larger vowel spaces, demonstrating more posterior tongue position, based on F1 and F2 values of the three corner vowels /-i/, /-a/ and /-u/, than monolingual speakers. No systematic implications were obtained regarding the effect of bilingualism on speech motor control. Despite the inconclusive findings, data from the present study shed light on understanding the effect of bilingualism on speech motor control.