Tone-induced split in stop category mapping by Korean learners of Mandarin Chinese

The present study reports a novel case where a simple one-to-one category mapping may develop into a systematic one-to-two mapping over the course of second language acquisition. We examined the split in category mapping of the Mandarin unaspirated stops conditioned by tone by Korean-speaking learners of Mandarin Chinese (e.g. Mandarin /ta³⁵/ to Korean lenis [ta] vs. Mandarin /ta⁵⁵/ to Korean fortis [t'a]). Korean L2 learners and naïve listeners participated in identification tasks in which f0contours of Mandarin words containing unaspirated stops with short-lag VOTs were digitally manipulated. In word-initial position, learners showed a near-categorical perception from lenis to fortis as f0increased, while most stimuli were identified as fortis by naïve listeners. The effect of f0was much smaller in word-medial position, but the group difference remained the same, confirming the two groups' differential use of phonetic cues for stop identification. Taken together, a substantial reorganization of perceptual cues, namely the promotion of f0 concurrent with significant underweighting of VOT cues, seems to have taken place during L2 acquisition. The findings were discussed with reference to PAM-L2 whereby the knowledge of the L2 phonological system along with particular phonetic properties of the L2 sounds may have driven a perceptual regrouping of the L2 stop categories.