Acquisition of L2 English Plural Forms in Korean and Chinese Learners: An ERP Study

While plural morphology in English is relatively straightforward, many L2 learners struggle to detect number agreement violations during processing. Focusing on the difference that Chinese lacks obligatory plural marking, whereas Korean marks plurality when used with demonstratives (in definite contexts) and optionally in other cases, this study examines whether advanced L2 learners who have different plural systems in their L1 (Chinese and Korean) can achieve native-like processing of number agreement, within the framework of the Morphological Congruency Hypothesis (MCH; Jiang et al., 2011), and whether L1 transfer occurs. The results showed that neither group reached native-like accuracy in the grammaticality judgment task, with no significant group differences emerging across definite and indefinite conditions. ERP data revealed no N400 or P600 effects in the definite condition for either group, but a weak P600 emerged for indefinite violations among Korean learners only. These findings are not completely consistent with the MCH, suggesting that morpheme congruency alone cannot fully explain the complexity of L2 learning. Moreover, when L1-L2 congruency exists only in specific language contexts, the congruent effect may be limited.