Lexical quality and executive control predict children’s first and second language reading comprehension

This study compared how lexical quality (vocabulary and decoding) and executive control (working memory and inhibition) predict reading comprehension directly as well as indirectly, via syntactic integration, in monolingual and bilingual fourth grade children. The participants were 76 monolingual and 102 bilingual children (mean age 10 years, SD = 5 months) learning to read Dutch in the Netherlands. Bilingual children showed lower Dutch vocabulary, syntactic integration and reading comprehension skills, but better decoding skills than their monolingual peers. There were no differences in working memory or inhibition. Multigroup path analysis showed relatively invariant connections between predictors and reading comprehension for monolingual and bilingual readers. For both groups, there was a direct effect of lexical quality on reading comprehension. In addition, lexical quality and executive control indirectly influenced reading comprehension via syntactic integration. The groups differed in that inhibition more strongly predicted syntactic integration for bilingual than for monolingual children. For a subgroup of bilingual children, for whom home language vocabulary data were available (n = 56), there was an additional positive effect of home language vocabulary on second language reading comprehension. Together, the results suggest that similar processes underlie reading comprehension in first and second language readers, but that syntactic integration requires more executive control in second language reading. Moreover, bilingual readers additionally benefit from first language vocabulary to arrive at second language reading comprehension.