Bilingualism and musicianship selectively facilitate non-native tone perception: Tone type and syllable variability matter

This study investigated how listeners’ language and music backgrounds jointly affect their non-native tone perception in the low variability condition, where tones were constantly borne by a fixed syllable, and in the high variability condition, where tones were always carried by different syllables. Using an AX discrimination task combined with low and high syllable variability manipulation, we asked four participant groups, including Mandarin-L1 monolinguals and Mandarin-L1 and Cantonese-L2 bilinguals with or without musical training, to make tone comparisons in Teochew, a complex tonal language unknown to them. Results of mixed-effects models on the sensitivity d’ values showed that all groups obtained higher d’ values when perceiving contour tones than level tones, and in the low variability condition than the high variability condition. This suggested effects of native phonology of tone on non-native tone perception and perceptual integration of non-native tones and syllables. Furthermore, bilinguals outperformed monolinguals in perceiving tones in the high variability condition, indicating bilinguals’ stronger ability to extract pitch information across stimulus variations. The bilingual advantage was also found in the perception of level tones, but not in contour tones, with musically trained bilinguals performing better than their non-musician peers. This suggested that listeners’ pitch sensitivity can be re-modulated by a tonal second language, with musicianship further amplifying this effect on non-saturated acoustic cues. Overall, these findings reveal that listeners’ previously acquired tonal languages and musical training integrally affect their non-native tone perception, and these combined effects are tailored by tone type and syllable variability. Both pedagogical and clinical implications are discussed.