Wed-1-10-10 The different enhancement roles of covarying cues in Thai and Mandarin tones

Abstract: Any phonological contrast is distinguished by multiple covarying cues. The role and nature of the cue covariation have been much debated in the literature, identifying the physiological link in production, perceptual integration, and enhancement as the key factors in play. In this study, we test whether the enhancement role of covarying cues are influenced by yet another factor: the interaction between cues at multiple layers of phonological structure. We hypothesize that further enhancement of the cue covariations occurs in contexts where acoustic cues are in competition for phonological contrasts at multiple prosodic levels. To test this, we investigate the enhancement role of the covariation relationship between F0 and spectral cues in Mandarin and Thai tones in different phrasal positions. Exploratory and multidimensional-scaling analyses suggest that in Mandarin, the phrase-final weakening of F0 cues are compensated by enhancing the spectral cues, while in Thai, tonal category-specific enhancement is observed at all phrasal positions. The context- and category- specific enhancement of covarying cues suggests that the language's phonological structure plays an important role in the fine-tuning of cue covariations.