Bilinguals need to learn two words for most concepts. These words are called translation equivalents, and those that also sound similar (e.g., banana–banane) are called cognates. Research has consistently shown that children and adults process and name cognates more easily than non-cognates. The present study explored if there is such an advantage for cognate production in bilinguals’ early vocabulary development. Longitudinal expressive vocabulary data were collected from 47 English–French bilinguals starting at 16–20 months up to 27 months (a total of 219 monthly administrations in both English and French). Children produced a greater proportion of cognates than non-cognates, and the interval between producing a word and its translation equivalent was about 10–15 days shorter for cognates than for non-cognates. The findings suggest that cognate learning is facilitated in early bilingual vocabulary development, such that phonological overlap supports bilinguals in learning phonologically similar words across their two languages.

Many human infants grow up learning more than one language simultaneously but only recently has research started to study early language acquisition in this population more systematically. The paper gives an overview on findings on early language acquisition in bilingual infants during the first two years of life and compares these findings to current knowledge on early language acquisition in monolingual infants. Given the state of the research, the overview focuses on research on phonological and early lexical development in the first two years of life. We will show that the developmental trajectory of early language acquisition in these areas is very similar in mono- and bilingual infants suggesting that these early steps into language are guided by mechanisms that are rather robust against the differences in the conditions of language exposure that mono- and bilingual infants typically experience.