Influences of bilingual input on English vocabulary size and academic outcomes: a large-scale longitudinal study following children in Australia from five to ten years

Research from large population-based studies investigating the language and academic outcomes for bilingual children is rare. The current study aimed to investigate the influence of dual language exposure on (i) English vocabulary outcomes at 5 years (126 bilinguals, 1675 monolinguals), and 10 years (vocabulary: 92 bilinguals, 1413 monolinguals:), and (ii) academic outcomes at 10 years (107 bilinguals, 1746 monolinguals). Participants were drawn from Generation 2 of the Raine Study, a longitudinal study from birth to 28 years (n = 2868, 88.3% white, 50.7% boys, 6.7% bilinguals) in Australia. At 5 years, bilinguals had lower receptive English vocabulary than monolingual peers (p <.05). No differences were found between groups in receptive vocabulary at 10 years, and groups were comparable on teacher-reported academic outcomes at 10 years. Findings suggest that dual language exposure (i.e. English as the societal language and another language at home) may impact vocabulary performance at the time of transition to formal education, however, these differences are not maintained in middle childhood, with no impact on academic performance at 10 years.