The Role of Language Dominance in Congruency Effects on Multi‐Word Unit Processing: Evidence From Early Bilinguals

ABSTRACT This study investigates how the learner‐related factors of language dominance, encompassing language history, proficiency, use, and attitude, modulate congruency effects in multi‐word unit (MWU) processing among early bilinguals. Seventy Cantonese–Putonghua bilinguals completed lexical decision tasks measuring reaction time and accuracy for congruent and incongruent MWUs in both languages. A language dominance questionnaire assessed participants’ language dominance across the four dimensions. Results revealed an asymmetrical pattern of the congruency effect in bilingual MWU processing. Specifically, a significant congruency effect was observed in Cantonese MWU processing, with language proficiency moderating this effect: higher proficiency of Putonghua was associated with faster processing of congruent Cantonese MWUs. In contrast, MWU congruency did not independently predict Putonghua MWU processing. Significant interaction effects emerged between MWU congruency and multiple dimensions of language dominance on Putonghua MWU processing. These findings underscore the role of language dominance in shaping congruency effect of bilingual MWU processing and suggest that bilingual lexical access could be graded, asymmetrical, and context sensitive.