Do First Language, Word Frequency and Input Matter in Bilingual’s Language Acquisition?

The acquisition of morphosyntactic features, such as third-person singular (3SG) inflection, is a critical aspect of language development. While much research has focused on monolingual children’s acquisition of 3SG inflection, less is known about how bilingual children navigate this process, particularly those from non-inflectional first language (L1) backgrounds. Furthermore, two well established characteristics found in other bilingual groups: word frequency and L1 transfer are still remain unclear in the acquisition of 3SG inflection in Chinese-English bilingual groups. Addressing these gaps are crucial for understanding the unique challenges bilingual children face and the factors influencing their acquisition of English morphosyntatic feature. In this study, we employed corpus to analyze longitudinal naturalistic data from three Chinese-English bilingual children and one English monolingual child. We investigated the children’s use of 3SG inflection across obligatory contexts, examining the frequency of verb exposure in both parental input and a large corpus (COCA). Our results indicate that bilingual children, especially those from a non-inflectional L1 background, demonstrated delayed acquisition of 3SG inflection compared to monolingual counterparts. However, both groups showed better accuracy with high-frequency verbs, underscoring the importance of input frequency. Additionally, L1 transfer effects were evident in both monolingual children and bilingual children, with the bilingual children struggling more with verbs whose L1 lacked verb agreement. These findings suggest that both input frequency and L1 transfer play significant roles in shaping bilingual children’s acquisition of 3SG inflection. This study contributes to a deeper understanding of bilingual language development, with implications for language acquisition theory and educational practices, particularly in addressing the needs of children from diverse linguistic backgrounds.