From eye to cortex: Tracing the neurocognitive dynamics of bilingual novel word acquisition

The current study examined how native language (L1) orthographic features influence bilinguals’ ability to rapidly form new representations for second-language (L2) written word forms. We assessed eye movements, neural activity, and behavioral performance in sequential bilinguals with L1-L2 orthographical pairs within (Spanish-English) and across (Mandarin Chinese-English) writing systems. Participants were trained on novel English words embedded in naturalistic sentence contexts, followed by a two-day post-training session. Analyses of eye-movement variables, fixation-related potentials, and learning outcomes revealed that Spanish-English bilinguals exhibited more automatic lexical encoding of novel words, reflected in shorter fixations and attenuated early neural responses, whereas Chinese-English bilinguals maintained prolonged attentional engagement across exposures. These divergent exposure-related dynamics predicted post-training performance, with Spanish bilinguals showing greater gains after consolidation. The findings suggest that the neuroplasticity underlying L2 word learning is shaped by pre-existing cortical circuits for native linguistic features, leading to different neural strategies for forming new lexical representations.