More like guidelines than hard rules: Bilinguals accept lexical overlap despite using mutual exclusivity.

Mutual exclusivity (ME), the tendency that young children have to select a novel object upon hearing a novel label, gives children a basis to select a referent for an unknown label. However, this strategy may not be relevant to bilinguals who learn multiple labels for most objects. Although previous research showed that bilinguals are better than monolinguals in accepting second labels for familiar objects, these studies explicitly labelled the familiar objects with a novel name, leaving open the question of whether children implicitly accept lexical overlap in ambiguous naming situation. We investigated to what extent monolingual and bilingual children associate a novel label with a familiar, name-known object when a novel object is present using a tablet-based referent selection task. Subsequently, we examined whether children retained the novel word-object association as well as whether they formed associations between the novel labels and the familiar, name-known objects. We tested 123 monolingual and 131 bilingual children between 3 and 10 years of age. We found that monolinguals and bilinguals relied on ME but bilinguals to a lesser extent than monolinguals. Monolinguals retained novel word-object associations but not the associations between novel words and familiar objects, while bilinguals retained the associations between novel words and familiar objects but not novel word-object associations. Our study extends the proposition that bilinguals are open to lexical overlap even in ambiguous referent selection situations. Our findings thus indicate that the influence of language experience on children's word-learning strategies persists throughout the first decade of life.