Cross-linguistic interference in late language learners: An ERP study

•Late language learners sensitive to syntactic violations at brain level (P600)•P600 for syntactic violations unaffected by gender congruency and cognate status.•Gender congruency is the driving factor in non-native syntactic decision making.•Support for gender-integrated representation hypothesis in late language learners.•Inhibitory skills unrelated to vocabulary size in late language learners. This study investigated cross-linguistic interference in German low-proficient late learners of Spanish. We examined the modulating influence of gender congruency and cognate status using a syntactic violation paradigm. Behavioural results demonstrated that participants were more sensitive to similarities at the syntactic level (gender congruency) than to phonological and orthographic overlap (cognate status). Electrophysiological data showed that they were sensitive to syntactic violations (P600 effect) already in early acquisition stages. However, P600 effect sizes were not modulated by gender congruency or cognate status. Therefore, our late learners of Spanish did not seem to be susceptible to influences from inherent noun properties when processing non-native noun phrases at the neural level. Our results contribute to the discussion about the neural correlates of grammatical gender processing and sensitivity to syntactic violations in early acquisition stages.