中文摘要：

本研究探讨个体二语语音辨别能力的差异来源。以母语为粤语（L1）的粤语-普通话双语者为研究对象，根据被试的普通话二语（L2）的辨音能力，将其分为二语辨音强组（GP）和二语辨音弱组（PP），以失匹配负波（MMN）为电生理指标通过 ERP 实验分别考察了两组被试对语音和一般声音（复合音）的辨别差异。结果发现：无论是对母语语音辨别还是对跨语系第三种语言的语音辨别，二语辨音强组的被试诱发的MMN波幅都显著大于二语辨音弱组的被试；进一步，对一般复合音的辨别，二语辨音强组的被试诱发的MMN波幅也显著大于二语辨音弱组的被试。研究结果表明：二语语音辨别的个体差异不仅可以追溯到一般语音层面的辨音能力差异，还可以进一步追溯到一般声音层面的复合音辨音能力差异。

英文摘要：

As to the origin of individual differences in perceiving the sounds of a second language, the scientific community has been divided. There are two alternative explanations： a general psychoacoustic origin vs. a general speech one. A previous study （Diaz et al., 2008） has shown that such individual variability is linked to the perceivers’ general speech abilities. However, our research casts doubt on the conclusion for two reasons. Firstly, this study exclusively focused on speech sounds in the same language family, rather than explored the languages from different language families. It has only been proved that individual variability in L2 is related to varied sensitivities to the speech sounds within the same language family rather than in the general speech system including different language families. Moreover, the study selected pure tones as acoustic materials, neglecting another important acoustic signals, complex sounds. It is obvious that we can＇t draw the conclusion that ability of processing general sounds has no impact on discrimination of speech sounds in L2, without studying complex tones. Here, studying speech sounds from different language families and complex sounds, the main purpose of present study was to explore whether the individual differences in perceiving L2 stem from their ability of processing general phonetic signals or phonetic stimuli within the specific language family, and farther explore whether such individual variability deeply stems from individual sensitivity to complex tones. In the present study, 14 L2 good perceivers （GP） and 14 L2 poor perceivers （PP）, in order to participate in the following ERP experiment, were selected from 130 healthy Cantonese （L1）-mandarin （L2） bilinguals according to their performances in a behavior task. To precisely measure the participants’ sound discrimination, MMN elicited by oddball paradigm was recorded in the following experiment. The ERP experiment consists of three sections, including native speech sounds, speec