Vocabulary production in toddlers from low-income immigrant families: evidence from children exposed to Romanian-Italian and Nigerian English-Italian.

The relationship between first and second language in early vocabulary acquisition in bilingual children is still debated in the literature. This study compared the expressive vocabulary of 39 equivalently low-SES two-year-old bilingual children from immigrant families with different heritage languages (Romanian vs. Nigerian English) and the same majority language (Italian). Vocabulary size, vocabulary composition and translation equivalents (TEs) were assessed using the Italian/L1 versions of the CDI. Higher vocabulary in Italian than in the heritage language emerged in both groups. Moreover, Romanian-Italian-speaking children produced higher proportions of TEs than Nigerian English-Italian-speaking children, suggesting that L1-L2 phonological similarity facilitates the acquisition of cross-linguistic synonyms.