Profiling bilinguals: The concurrent and longitudinal associations between executive function and reading proficiency

This study compared executive function among subgroups of Hong Kong bilingual children with varying proficiency in their first-language (L1) Chinese and second-language (L2) English. It also assessed the concurrent and longitudinal contributions of executive function to their L1 and L2 word reading and reading comprehension. Latent profile analyses identified three bilingual groups: Cantonese-dominant with low L2 ( n = 88, 26.67%), Cantonese-dominant with average L2 ( n = 115, 34.85%), and balanced bilinguals with high L2 ( n = 127, 38.48%). While the two Cantonese-dominant groups performed comparably on executive function, the balanced bilinguals outperformed both. Executive function concurrently and longitudinally predicted reading comprehension in L2 English but not in L1 Chinese, with a stronger association found for the Cantonese-dominant group with average L2 compared to the other two groups. These findings highlight the influence of heterogeneity of bilingual's language proficiency on executive function and the relation between executive function and reading development. The mixed evidence on bilingual children's executive function advantage complicates the relationship between executive function and reading development. Our study demonstrated for the first time that Hong Kong Chinese-English bilingual children's executive function skills were moderated by the level of proficiency in their first (L1) and second (L2) languages. Balanced bilinguals outperformed Cantonese-dominant peers in executive function, while executive function predicted L2 but not L1 reading, most strongly for the Cantonese-dominant group with average L2. These findings underscore the role of bilingual proficiency in cognitive-literacy linkages. Thus, instead of employing a uniform strategy, educators should consider how varying degrees of L1-L2 proficiency influence executive function and biliteracy development, particularly when supporting L2 acquisition in linguistically diverse classrooms. • Three distinct profiles exist among Hong Kong Chinese-English bilingual children. • Balanced bilinguals outperformed L1-dominant bilinguals in executive function (EF). • Variability of processing speed captured EF heterogeneity in bilinguals. • EF predicted L2 English reading comprehension concurrently and longitudinally. • Bilingual heterogeneity is crucial for designing future reading instruction.