This study examined individual-level variability in N400 and P600 ERP correlates of native and nonnative language sentence processing of semantic and grammar information. Twenty-six native English-speaking learners of Spanish as a second language were tested. Participants completed sentence reading tasks in English and Spanish during EEG recording. The group-level results for grammar showed P600s in the native and nonnative language. For semantics, there was an N400 only in the native language. Individual-level ERP patterns revealed that, for native language semantics, about two thirds of participants showed N400s, but approximately one-third showed P600s. For native language grammar, approximately one third of participants exhibited N400s instead of P600s. Individual-level ERPs showed similar variability in the nonnative language for semantics and grammar, and N400/P600 variability in Spanish related to Spanish verbal fluency and grammar knowledge. This contributes knowledge of how nonnative and native language neurocognition compare regarding the processing routes that individuals use during comprehension.

本研究检查了 N400 和 P600 ERP 中个体水平的变异性，这些差异与语义和语法信息的母语和非母语句子处理相关。对 26 名以英语为母语、以西班牙语为第二语言的学习者进行了测试。参与者在脑电图记录期间完成了英语和西班牙语的句子阅读任务。语法的组级结果显示母语和非母语的 P600。对于语义，只有母语的 N400。个人级别的 ERP 模式显示，对于母语语义，大约三分之二的参与者显示 N400，但大约三分之一的参与者显示 P600。对于母语语法，大约三分之一的参与者展示了 N400 而不是 P600。个人水平的 ERP 在非母语语义和语法方面表现出相似的变异性，而西班牙语的 N400/P600 变异性与西班牙语口语流利性和语法知识相关。这有助于了解非母语和母语神经认知如何比较个人在理解过程中使用的处理路径。