Influences of Bilingualism and Developmental Language Disorder on How Children Learn and Process Words

Previous studies found that bilingual children and adults with typical language development (TLD) perform better than monolinguals in novel word learning, but show lower scores on lexical retrieval tasks (e.g., naming known words). Children with developmental language disorder (DLD) lack in their abilities in both tasks compared with children with TLD. The current study tested the interplay between bilingualism and language disorder during novel word learning and lexical retrieval. Preschoolers (N = 101; 50 boys and 51 girls; mothers’ mean years of education = 16.35) in four groups (Hebrew monolinguals or Russian-Hebrew bilinguals with DLD or TLD) learned 12 novel real words (6 with a familiar referent and 6 with a novel referent) and performed a lexical retrieval task. Children exhibited significant learning with no effect of bilingualism, but a negative effect of language disorder. Thus, children with DLD performed worse than children with TLD, and this ability was not affected by bilingualism. In lexical retrieval, DLD groups scored lower than TLD groups, and critically also bilinguals scored lower than monolinguals. This differential effect of bilingualism in the two tasks suggests that bilingualism does not impede language learning mechanisms even among children with DLD. Instead, the findings suggest that lower performance in the lexical retrieval task is due to decreased frequency of exposure. By exploring both word learning and lexical retrieval, the study highlights the differential mechanisms at play in the effects of bilingualism and language disorder on the developing lexicon.