This study examined the correlates of different aspects of vocabulary knowledge in L1 Chinese and L2 English in Hong Kong bilingual children (N = 481, age = 6–12 years old). Their nonverbal IQ, cognitive-linguistic skills, receptive and expressive vocabulary knowledge breadth, and vocabulary knowledge depth in Chinese and English were measured. Results demonstrated that morphological awareness was uniquely correlated with different aspects of vocabulary knowledge across Chinese and English. Phonological processing skills played different roles in vocabulary knowledge in L1 and L2. In addition, receptive vocabulary breadth uniquely contributed to expressive vocabulary breadth across languages. Moreover, both receptive and expressive vocabulary breadth contributed to vocabulary knowledge depth in L1 Chinese and L2 English. The findings highlight some shared and unique aspects of different vocabulary constructs across languages.
