Previous studies have demonstrated that the second language (L2) learners' linguistic backgrounds and L2 proficiency have an effect on their perception of L2 sounds. This paper attempts to investigate the assimilation patterns of Mandarin and Tibetan tones, and the influences of first language (L1) backgrounds and Mandarin proficiency on the perception of Mandarin tones. A total of 46 Tibetan participants, including 14 Khams and 32 U-Tsang speakers, were instructed to assimilate the Mandarin tones they've heard to their most similar native tones. Results suggest that the four-tone system U-Tsang speakers match M155 to T155, M451 to T452, with great disparities in mapping M235 and M3214 to T213 and T3132, while the two-tone system Khams speakers tend to assimilate M155 and M451 to the high tone, and M235 and M3214 to the low tone. Mandarin Chinese proficiency does show the progressive tone-mapping patterns, that is, the higher the learners' proficiency is, the more possible he or she will have the tone mapping which could be predicted by the tone values. As proficiency level increases, standard deviation of learners' mapping tends to get smaller, especially among Khams speakers.
Bibliographic reference. Bao, Wenfu / Feng, Hui / Dang, Jianwu / Liu, Zhilei / Yu, Yang / Wang, Siyu (2015): "Perception of Mandarin tones by native tibetan speakers", In INTERSPEECH-2015, 811-814.