Bilingual effects on lexical selection: A neurodevelopmental perspective

•When processing spoken language, multiple lexical items may compete for selection.•We used fNIRS to measure children’s brain activity when processing linguistic competitors.•Bilingual and monolingual children activated fronto-parietal brain regions.•Monolinguals engaged greater brain activity in left frontal regions than bilinguals.•Bilingualism adapts top-down frontal lobe functions, likely to process dual-lexicons. When a listener hears a word, multiple lexical items may come to mind; for instance, /kæn/ may activate concepts with similar phonological onsets such as candy and candle. Acquisition of two lexicons may increase such linguistic competition. Using functional Near-Infrared Spectroscopy neuroimaging, we investigate whether bilingualism impacts word processing in the child’s brain. Bilingual and monolingual children (N = 52; ages 7–10) completed a lexical selection task in English, where participants adjudicated phonological competitors (e.g., car/cat vs. car/pen). Children were less accurate and responded more slowly during competing than non-competing items. In doing so, children engaged top-down fronto-parietal regions associated with cognitive control. In comparison to bilinguals, monolinguals showed greater activity in left frontal regions, a difference possibly due to bilinguals’ adaptation for dual-lexicons. These differences provide insight to theories aiming to explain the role of experience on children’s emerging neural networks for lexical selection and language processing.