Lexical Development in Bilingual French/ Portuguese Speaking Toddlers

In this study, we explore if French-European Portuguese (EP)-speaking bilingual toddlers produce the same number of words as their monolingual peers, in French, in EP, or in both languages. Furthermore, we explore the link between language dominance and lexicon size. We tested 53 bilingual French-EP children, among which 16 were 16–18 months old, 16 were 24–25 months old and 21 were 30–35 months old. The parents completed the French and the EP Communicative Development Inventory (adaptations of MacArthur–Bates CDI [Fenson et al., 2007]), the PaBiQ (Tuller, 2015) to evaluate language dominance and the ASQ-3 (Squires et al., 2009) to assess their developmental stages. The total vocabulary (both language combined, TV?F+EP), the total vocabulary (TV) in each language (TV?EP and TV?F) and the conceptual vocabulary (CV) were calculated. These vocabulary measures were compared with the monolingual norms in French and EP. The results showed that almost all participants had the same performance in vocabulary acquisition as their monolingual peers in French and EP, measured through the CDI in each language respectively. Their TV?F+EP and CV exceeded the vocabulary of monolinguals and language dominance was correlated with vocabulary size.