Labial Activation in Plosives in L2 English by Mandarin Speakers

Résumé

The current study investigated how the production of English bilabial plosives in various word positions (i.e., initial, medial, final) affects orbicularis oris (OO) muscle activation between L1 Mandarin-L2 English speakers and L1 English speakers. Surface electromyography (sEMG) recorded OO muscle activity as electrical signals measured in millivolts (mV) over time (ms) from 20 participants (12 L1 English speakers, 8 L1 Mandarin-L2 English speakers). Audio recordings were transcribed in Praat (Boersma & Weenink, 2024), force-aligned using Montreal Forced Aligner (McAuliffe et al., 2017), and analyzed in EMGWorks (Delsys, 2021). Previous research (Ng and Chiew, 2023) examined the VOT of English word-initial plosive consonants in L1 Mandarin-English speakers and found weaker voicing contrasts. Furthermore, we hypothesized that there would be an L1 transfer of phonological rules from L1 Mandarin that would influence L1 Mandarin-L2 English speaker production of English sounds to follow L1 phonological restrictions compared to those of an English L1 speaker. Specifically, L1 Mandarin-L2 English speakers will have a stronger OO muscle activation for /p/ compared to /b/ in all word positions, with the greatest activation for both sounds occurring respectively in word-initial, medial, and final positions. L1 Mandarin-L2 English speakers will also have weaker activation than English L1 speakers’ production of /b/ in all word positions, whereas /p/ will have weaker activation in only the word-final position. The results showed that L1 Mandarin speakers demonstrated different activation for /b/ across the three word positions compared to L1 English speakers. Additionally, L1 Mandarin muscle activation varied with word position, with the greatest activation being initial. Finally, further research can expand on other muscles involved in bilabial production and integrate visual tools through OpenFace (Baltrušaitis et al., 2016).