Individual differences in the production of referential expressions: The effect of language proficiency, language exposure and executive function in bilingual and monolingual children

One hundred and seventy-two English-speaking 5- to 7-year-olds participated in a referential communication task where we manipulated the linguistic mention and the visual presence of a competitor alongside a target referent. Eighty-seven of the children were additionally exposed to a language other than English (bilinguals). We measured children's language proficiency, verbal working memory (WM), cognitive control skills, family SES, and relative amount of cumulative exposure and use of the home language for the bilinguals. Children's use of full Noun Phrases (NPs) to identify a target referent was predicted by the visual presence of a competitor more than by its linguistic mention. Verbal WM and proficiency predicted NP use, while cognitive control skills predicted both the ability to use expressions signalling discourse integration and sensitivity to the presence of a discourse competitor, but not of a visual competitor. Bilingual children were as informative as monolingual children once proficiency was controlled for.