Non-native perception of the Japanese singleton/geminate contrast: comparison of Mandarin and Mongolian speakers differing in Japanese experience

Japanese is a quantity language that uses durational variation contrastively for both vowels and consonants. Therefore, correct use of contrastive length is important for efficient communication. However, it is widely acknowledged that length contrast is difficult for non-native speakers from diverse first language (L1) backgrounds. To examine the effects of L1 and Japanese learning experience on consonant length (i.e., short/singleton vs long/geminate) processing, we compared the perception of Japanese singleton/geminate by native speakers of Mandarin and Mongolian at different levels of Japanese experience. A group of 10 native Japanese speakers participated as controls. Neither Mandarin nor Mongolian uses consonant length contrastively, but Mongolian uses vowel length contrastively. Further, unlike Japanese and Mandarin, Mongolian frequently uses closed syllables and permits a wide range of consonants in coda position. The participants responded to 200 trials via the AXB discrimination task. All Mandarin groups, including the most advanced one, were significantly less accurate than the Japanese group. On the other hand, none of the Mongolian groups, including the one without Japanese experience, differed from the Japanese group. The most advanced Mandarin group was the closest to (and did not significantly differ from) the Mongolian groups, showing a positive effect of Japanese learning.