Organization of acoustic voice quality variation within and between Persian-English bilinguals: A principal component analysis

Abstract

Auditory discrimination of bilingual voices has proven to be challenging for listeners. This can be attributed to the structure of acoustic voice dimensions, which depends not only on speaker-specific acoustic features but also on language-dependent characteristics. This study investigates how acoustic voice dimensions vary within and between Persian-English bilingual speakers and how constellations of voice quality parameters operate within different languages across speakers. Acoustic voice quality indices were computed over voiced segments from read speech samples of 40 gender-balanced Persian-English bilingual speakers. Using a psychoacoustic model developed by Kreiman, Gerrat, Garellek, Samlan, and Zhang [Loquens 1(1), e009 (2014)] and principal component analyses, we found that only a few acoustic voice dimensions are shared within and between speakers. However, most acoustic variability within and between speakers remains idiosyncratic, suggesting that “individual” and “general” voice spaces are similarly structured within and between speakers in each language context, i.e., Persian and English. Comparing the underlying structures of Persian and English, we found that speakers follow similar acoustic patterns in their two languages. However, some divergences exist between Persian and English acoustic structures, especially for female speakers, which could have implications for bilingual voice discrimination. © 2025 Acoustical Society of America.