Factors affecting voice onset time in English stops English proficiency, gender, place of articulation, and vowel context

This study investigates the voice onset time (VOT) of L₂ English stops produced by native speakers of Chinese at different L₂ proficiency levels. Four factors were examined: English proficiency, gender, place of articulation, and vowel context. High and low achievers of English were recruited as the experimental groups and native speakers of English as the control group. Each group consisted of 16 participants, 8 males and 8 females. Each participant took part in a read-aloud task, in which the target words were presented in an embedded sentence. The results showed that the effects of L₂ proficiency were significant in that high achievers outperformed low achievers who were affected by L₁ negative transfer more seriously when producing native-like English stops. Additionally, when producing English stops, velar stops had significantly greater VOT values than either bilabial or alveolar ones. However, no significant gender differences were found. Male and female participants produced similar VOT values in English stops. Last, the vowel context was also a significant factor. The VOT lengths differed according to the context of a following vowels. More specifically, the VOT of a stop is significantly longer when followed by a tense vowel.