Voice Perception Across Languages: Reduced Similarity Between Speakers, Stable Identity Within Speakers

PURPOSE: Despite the central role of voice perception in social interaction, the mechanisms underlying cross-linguistic voice similarity judgments remain underexplored. This study examined how voice similarity is perceived within and across languages, using bilingual speech as a means to isolate language-driven effects while controlling for anatomical variation. METHOD: English-speaking listeners with and without Cantonese proficiency completed a perceptual similarity rating task involving Cantonese-English bilingual speakers. Listeners rated the similarity of voice pairs on a 9-point scale, including both within-language and cross-language comparisons. Multidimensional scaling (MDS) was applied to the dissimilarity ratings to model perceptual voice space, and acoustic-perceptual correlations were used to relate perceptual dimensions to acoustic properties of the speech signal. RESULTS: Cross-language voice pairs were perceived as significantly more dissimilar than within-language pairs, particularly for same-speaker items, indicating a language mismatch effect. No robust language familiarity effect was observed between listener groups. Importantly, same-speaker pairs were consistently judged as more similar than different-speaker pairs even across languages-a finding further supported by MDS, which revealed a stable underlying perceptual structure in which speakers generally clustered with themselves across languages. Perceptual dimensions were primarily associated with pitch, vocal tract size, and harmonic-to-noise spectral characteristics, with their relative weighting modulated by language context. CONCLUSIONS: The findings indicate that while language mismatch reduces perceived similarity between speakers, the vocal identity of a speaker remains perceptually stable across languages. These results refine the prototype model of voice perception by demonstrating dynamic, context-sensitive weighting of acoustic cues in bilingual voice processing. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.34717377.