The combined effects of bilingualism and musicianship on listeners' perception of non-native lexical tones

Non-native lexical tone perception can be affected by listeners' musical or linguistic experience, but it remains unclear of whether there will be combined effects and how these impacts will be modulated by different types of non-native tones. This study adopted an orthogonal design with four participant groups, namely, Mandarin-L1 monolinguals and Mandarin-L1 and Cantonese-L2 bilinguals with or without musical training, to investigate effects of bilingualism and musicianship on perception of non-native lexical tones. The closely matched four groups, each encompassing an equal number of 20 participants, attended a modified ABX discrimination task of lexical tones of Teochew, which was unknown to all participants and consists of multiple tone types of level tones, contour tones, and checked tones. The tone perceptual sensitivity index of d' values and response times were calculated and compared using linear mixed-effects models. Results on tone sensitivity and response time revealed that all groups were more sensitive to contour tones than level tones, indicating the effect of native phonology of Mandarin tones on non-native tone perception. Besides, as compared to monolinguals, bilinguals obtained a higher d' value when discriminating non-native tones, and musically trained bilinguals responded faster than their non-musician peers. It indicates that bilinguals enjoy a perceptual advantage in non-native tone perception, with musicianship further enhancing this advantage. This extends prior studies by showing that an L2 with a more intricate tone inventory than L1 could facilitate listeners' non-native tone perception. The pedagogical implications were discussed.