Voice Onset Time stimulus response in different levels of Japanese bilingual listeners

Kenzo Kimura* & Valerie Shafer, PhD

This study examines Voice Onset Time (VOT) in sequential, simultaneous bilingual Japanese-speaking adults, aged 18 to 25 years, and monolingual Japanese-speaking adults. Sequential bilinguals will be Japanese speakers who have learned English later on in life. In contrast, simultaneous bilinguals will have learned both Japanese and English at the same time and have no significant difference in language dominance. We predicted differences between sequential and simultaneous bilingual adults but no differences between monolinguals and sequential bilinguals, given that adults in the latter group have the same language exposure as monolingual Japanese. Previous studies have indicated that Japanese and English vowel pronunciations are similar, however, we aim to fill the gap that asks if bilingual learning levels impact VOT stimulus-response based on stop-consonants (Nakashima, 1998). Adults participated in a behavioral study in which they listened to a synthetic male speech that produced target words containing stop consonants in the word-initial position. Analyses examined the effect of bilingualism and control variables (age, place of articulation (PoA), vowel type) on positive VOT values and on the presence of lead voicing. Previous recorded language samples such as Portuguese and Spanish bilingual speakers were also included in our conclusion to observe VOT across other bilingual speakers. Expected results are that monolinguals and sequential bilinguals produce target voiced and voiceless stops with positive VOTs of similar magnitude. However, adults who are dominant in Japanese are expected to have shorter VOTs than simultaneous bilinguals, consistent with an influence of L1 on previous studies. Our study considered how age, bilingual experience, and vowel type influence VOT.