The modulatory role of L1 and L2 morphosyntactic similarity during production of L2 inflected words: An ERP study

•ERPs show that Korean-English bilinguals employ native-like morphological composition.•Chinese-English bilinguals employ whole-word processing in morphosyntax.•Morphosyntactic similarity modulates the production of L2 inflections.

The current study used ERP methodology to explore how morphosyntactic similarity between a first language (L1) and a second language (L2) affects L2 production of inflected words. Chinese-English bilinguals, Korean-English bilinguals, and Native English speakers were required to produce regular and irregular past tense verbs in English. Results showed that native English speakers and Korean-English bilinguals elicited more negative amplitudes in regular past tense verbs than in irregular ones 250-350 ms post-stimulus, whereas Chinese-English bilinguals did not, indicating that Korean-English bilinguals and native English speakers share similar processing mechanisms. These findings support a dual-system model (Ullman, 1999) and demonstrate that intermediate proficiency L2 learners can employ rule-based decomposition and combination to process regular words as native-speakers do, but mainly under the condition that L2 shares similar morphosyntax with L1, as Korean does with English. Our findings suggest that morphosyntactic similarity plays a modulatory role during production of L2 inflected words by bilinguals.