Stop Laryngeal Distinctions Driven by Contrastive Effects of Neighboring Tones

This study examined contrastive effects of neighboring tones that give rise to a systematic asymmetry in stop perception. Korean-speaking learners of Mandarin Chinese and naïve listeners labeled voiceless unaspirated stops preceded or followed by low or high extrinsic tonal context (e.g., ma^LO.pa vs. ma^HI.pa) either as lenis (associated with a low F0 at the vowel onset) or as fortis stops (with a high F0). Further, the target tone itself varied between level and rising (e.g., ma^LO.pa^LEV vs. ma^LO.pa^RIS). Both groups of listeners showed significant contrastive effects of extrinsic context. Specifically, more lenis responses were elicited in a high tone context than in a low one, and vice versa. This indicates that the onset F0 of a stop is perceived lower in a high tone context, which, in turn, provides positive evidence for lenis stops. This effect was more clearly pronounced for the level than for the contour tone target and also for the preceding than for the following context irrespective of linguistic experience. Despite qualitative similarities, learners showed larger effects for all F0 variables, indicating that the degree of context effects may be enhanced by one's phonetic knowledge, namely sensitivity to F0 cues along with the processing of consecutive tones acquired through learning a tone language.