Second language (L2) learners frequently encounter persistent difficulty in perceiving certain non-native sound contrasts, i.e., a phenomenon called “phonological deafness”. However, if extensive L2 experience leads to neuroplastic changes in the phonological system, then the capacity to discriminate non-native phonemic contrasts should progressively improve. Such perceptual changes should be attested by modifications at the neurophysiological level. We designed an EEG experiment in which the listeners’ perceptual capacities to discriminate second language phonemic contrasts influence the processing of lexical-semantic violations. Semantic congruency of critical words in a sentence context was driven by a phonemic contrast that was unique to the L2, English (e.g.,/ɪ/-/i:/, ship – sheep). Twenty-eight young adult native speakers of French with intermediate proficiency in English listened to sentences that contained either a semantically congruent or incongruent critical word (e.g., The anchor of the ship/*sheep was let down) while EEG was recorded. Three ERP effects were found to relate to increasing L2 proficiency: (1) a left frontal auditory N100 effect, (2) a smaller fronto-central phonological mismatch negativity (PMN) effect and (3) a semantic N400 effect. No effect of proficiency was found on oscillatory markers. The current findings suggest that neuronal plasticity in the human brain allows for the late acquisition of even hard-wired linguistic features such as the discrimination of phonemic contrasts in a second language. This is the first time that behavioral and neurophysiological evidence for the critical role of neural plasticity underlying L2 phonological processing and its interdependence with semantic processing has been provided. Our data strongly support the idea that pieces of information from different levels of linguistic processing (e.g., phonological, semantic) strongly interact and influence each other during online language processing.

第二语言（L2）的学习者在感知某些非母语的声音对比时经常遇到持续的困难，即被称为“语音聋”的现象。但是，如果广泛的L2经验导致音系中神经塑性的变化，则辨别非本机音素对比的能力应逐步提高。这种感觉变化应通过神经生理学水平的改变来证明。我们设计了一个脑电图实验，在该实验中，听众辨别第二语言语音对比的感知能力会影响词汇语义冲突的处理。句子上下文中关键词的语义一致性是由L2，英语（例如，/ɪ/-// i：/，船–羊）独有的音素对比所驱动的。）。二十八位讲法语的中级成年母语人士，英语水平中等，听了一些句子，这些句子包含语义上一致或不一致的关键单词（例如，船锚 / *绵羊 的锚被压低了）），同时记录了脑电图。发现三种ERP效果与L2水平的提高有关：（1）左额额听觉N100效果，（2）较小的额中音调失调负（PMN）效果，以及（3）语义N400效果。在振荡标记上未发现熟练程度的影响。当前的发现表明，人脑中的神经元可塑性甚至可以使后期获得甚至硬连线的语言特征，例如用第二种语言区分音素对比。这是首次提供行为和神经生理学证据，证明L2语音处理及其在语义处理中的相互依赖性背后的神经可塑性的关键作用。我们的数据强烈支持以下观点：来自不同语言处理级别的信息（例如，