The bilingual voice: Vocal characteristics when speaking two languages across speech tasks

Abstract

The present study compares vocal parameters in bilinguals’ use of two languages across different speech tasks, in order to examine whether language selection and task type will manifest different outcomes. Korean-English (KE) and Mandarin-English (ME) speakers performed three speech tasks – a reading passage, a monologue, and a picture description – in their two spoken languages. Fundamental frequency (F0), F0 variability, intensity, and speaking rate were measured. Results yielded an effect of language on average F0s, as both bilingual groups showed a significantly higher F0 in Mandarin or Korean compared to English. For the KE group, a higher F0 appeared in Korean compared to English across all tasks, while for the ME group, a difference in F0 between Mandarin and English was found for reading only. Both groups had the highest F0s in the reading task. There was a difference in F0 variability between two spoken languages only for the KE group monologue. Mean intensity of the ME group was overall higher than that of the KE group. Speaking rate was significantly slower in English than the native language for both groups, but the KE group demonstrated a greater difference in pace between their two spoken languages. Findings demonstrated that bilingual speakers produced notably different voice patterns contingent on language and speech task, indicating that inter- and intra-speaker variability in speakers’ vocal features can be attributed in part to language effects.