The role of language similarity in processing second language morphosyntax: Evidence from ERPs

This study investigated the role of L1–L2 morphosyntactic similarity in L2 learners of French. In two experiments, we manipulated the grammatical gender agreement between an adjective and noun in a sentence context. The noun either shared lexical gender across Spanish and French (Experiment 1) or did not (Experiment 2). ERPs were collected from beginner Spanish-speaking learners of French and native French speakers while they read sentences in French. The results for the native speakers revealed a P600 effect on gender agreement violations irrespective of lexical gender overlap across languages. L2 learners exhibited a negativity in the N400 time window in response to gender agreement violations that involved nouns with the same gender in their L1 and L2 (Experiments 1 and 2), whereas no difference was observed to gender agreement violations that involved nouns with contradictory gender across languages (Experiment 2). These results suggest that L2 learners at low levels of L2 proficiency rely on their L1 lexical gender system to detect gender agreement errors in L2, but engage different neurocognitive mechanisms to process similar L2 morphosyntactic knowledge. •Native speakers and learners of French processed gender agreement violations.•Nouns could share, or not, lexical gender across languages.•Language similarity facilitates processing for learners of French.•Learners show different neurocognitive mechanism compared to native speakers.•L2 learners rely on their L1 lexical gender system to process agreement in L2.