Bilingual mind in action: ERP evidence for semantic representation during code-switched metaphor comprehension

This study investigates the differences in processing metaphorical and literal sentences among Vietnamese-Chinese bilinguals using ERP to analyze bilingual representation mechanisms across various contextual conditions. As time-locked, scalp-recorded voltage deflections, Event-related Brain Potentials (ERPs) serve as a powerful measure, yielding sub-second temporal resolution for characterizing the neural mechanisms that support psychological and linguistic functions. In Experiment 1, participants evaluated metaphorical and literal sentences in both Chinese and Vietnamese. The results indicated that in the Vietnamese context did metaphorical sentences evoke significantly different ERP responses compared to literal sentences, particularly a larger N400 amplitude. This supports the Conceptual Integration Theory. Additionally, notable differences in P200 and N400 amplitudes were observed between L2(Chinese) and L1(Vietnamese) metaphorical sentences, suggesting independent representation of lexical forms and semantics in bilinguals. Experiment 2 demonstrated that metaphorical terms presented in Chinese within a Vietnamese context triggered a larger P200 and a smaller N400 amplitude. These findings support the independent representation of the two languages, emphasizing the co-activation and competition of bilingual lexicons, which aligns with the Inhibitory Control model of the Non-Specificity Hypothesis. This study pioneers the use of ERPs to show that Vietnamese-Chinese bilinguals simultaneously activate and compete lexicons of both languages during metaphor processing, providing the first electrophysiological evidence for language-non-specific inhibitory control in bilingual metaphor comprehension.