This study explored whether children's second language (L2) vocabulary, syntactic awareness, and reading comprehension contributed to the growth of each other. A total of 184 Chinese primary school children (91 girls) aged 8–10 years old in Hong Kong participated in the pre-test of this study. Among them, 88 were in Grade 3 and 96 were in Grade 4. One year later, 178 of these children also participated in the post-test. These children learned English as an L2 at school. They completed a series of English language tasks. The results from a cross-lagged panel model show that vocabulary predicted the growth of syntactic awareness and reading comprehension. Syntactic awareness predicted the growth of vocabulary and reading comprehension. Reading comprehension facilitated the growth of vocabulary, and it also predicted the growth of syntactic awareness in Grade 4 students but not in Grade 3 students. Implications for teaching children an L2 are discussed. Copyright © 2022 Elsevier Ltd. All rights reserved.

In a two-year longitudinal study we examined if and how syntactic awareness in L1 Chinese influenced reading comprehension in L2 English, a typologically different script. Participants were 401 Chinese-English bilingual children from Hong Kong. We assessed their word order, morphosyntactic, and reading comprehension skills in L1 Chinese and L2 English, and retested them after one year. Results showed that L1 syntactic awareness cross-linguistically predicted L2 reading comprehension over time; this prospective relationship was mediated by L2 syntactic awareness but not L1 reading comprehension. Moreover, similarity in syntactic structure was important in determining the degree of transfer. The comparable word-order structure between L1 and L2, thus less syntactic distance, rendered word order awareness more transferable than morphosyntactic awareness. Our findings suggest that teachers may evoke L1 syntactic features and map them onto L2 corresponding structures to facilitate reading comprehension in L2. Copyright © 2020 The Authors. Published by Elsevier Ltd.