The Predictive Role of Quantity and Quality Language-Exposure Measures for L1 and L2 Vocabulary Production among Immigrant Preschoolers in Italy

In this study, we investigated the lexical ability in L1 and L2 of 60 immigrant children who were 37 to 62 months old and exposed to minority languages (L1) and Italian (L2). Using the MacArthur–Bates Communicative Development Inventories, we measured children’s vocabulary production in L1 and L2. From interviews, we collected data on quantitative language exposure (parental input, child output, length of exposure to L2 at preschool, and parental oral fluency) and qualitative home-language exposure (HLE) practices (active, play, and passive) in L1 and L2. We conducted stepwise regression analyses to explore which factors predicted children’s vocabulary production in L1 and L2. The child’s chronological age and parental education were not predictors of vocabulary production. L2 parental input, L1 child output, and L1 HLE-active practices explained 42% of the variance in children’s L1 vocabulary production. L2 child output and L2 HLE-active practices explained 47% of the variance in children’s L2 vocabulary production, whereas length of L2 exposure in preschool was a predictor only when we included quantitative language-exposure factors in the model. The effects of the quantity and quality of language exposure on lexical ability among preschool immigrant children are discussed.