When exceptions matter: bilinguals regulate their dominant language to exploit structural constraints in sentence production

What we say generally follows distributional regularities, such as learning to avoid "the asleep dog" because we hear "the dog that's asleep" in its place. However, not everyone follows such regularities. We report data on English monolinguals and Spanish-English bilinguals to examine how working memory mediates variation in a-adjective usage (asleep, afraid), which, unlike typical adjectives (sleepy, frightened), tend to resist attributive use. We replicate previous work documenting this tendency in a sentence production task. Critically, for all speakers, the tendency to use a-adjectives attributively or non-attributively was modulated by individual differences in working memory. But for bilinguals, a-adjective use was additionally modulated by an interaction between working memory and category fluency in the dominant language (English), revealing an interactive role of domain-general and language-related mechanisms that enable regulation of competing (i.e. attributive and non-attributive) alternatives. These results show how bilingualism reveals fundamental variation in language use, memory, and attention.