Neural encoding of Cantonese and Vietnamese tones

Abstract

The present pilot study investigates the neural encoding of lexical tones in Cantonese and Vietnamese. Better encoding of tones was found in native than non-native tone language speakers in previous research, with fewer studies examining language-specific effects. An identical equipment setup was used to measure neural responses to three lexical tones in Hong Kong (HK) (by Cantonese speakers) and Ho Chi Minh City (by Vietnamese speakers). The three tones were the high rising (35), dipping (214), and low falling (21) tones, of which the 21 and 214 tones were unique to Cantonese and Vietnamese respectively. If better tone encoding is language-specific, Vietnamese and Cantonese adult speakers are expected to show enhanced encoding of these tones. Across the majority of temporal and spectral measures, we did not find significant group differences across tonal categories, suggesting that enhancement of neural encoding found in native speakers was likely to be language general. If confirmed with a larger sample size, these findings may suggest that clinical tools utilizing speech stimuli for the assessment of spoken language processing and its related functions may not necessarily require customization for a specific language. [Work supported by ITF in HK.]