Effect of Language on Voice Quality: An Acoustic Study of Bilingual Speakers of Mandarin Chinese and English

INTRODUCTION: Previous studies reported discrepant vocal qualities associated with different languages. However, possible physical differences associated with speakers of different ethnicities were not accounted for. The present study attempted to examine the effect of language on one's voice quality by eliminating the potential effects of physical differences associated with speakers of different languages. METHODS: Sixteen Chinese and fourteen Americans who were proficient in both Mandarin Chinese and English were recruited. They were instructed to read one Chinese and one English passage. Time-domain and long-term average spectral analyses were carried out, and speaking fundamental frequency (sF0), jitter, shimmer, and first spectral peak (FSP), mean spectral energy (MSE), and spectral tilt (ST) were measured using Praat. RESULTS: Acoustic measures revealed no differences in sF0, FSP, and ST between Americans and Chinese. However, jitter, shimmer, and MSE values appeared to be affected by ethnicity (Chinese vs. Americans). Jitter and shimmer tended to be greater when someone was speaking his/her mother tongue. For language effect, Chinese was found to be associated with a faster rate of vocal fold vibration than English. MSE was higher for Chinese than English produced by Chinese, but not by American speakers, despite the similar ST in both languages. DISCUSSION/CONCLUSION: Based on speech samples obtained from the balanced groups of bilingual speakers, the findings confirmed the presence of language effect on one's voice quality. Laryngeal activity appeared to be affected by the language being spoken.