Development of L1-L2 naming skills in a monolingual context: Evidence from children and adolescents

Adolescence is marked by significant developmental changes that can influence language processing and control. This study aimed to uncover developmental differences in language co-activation and control in unbalanced Spanish (L1)-English (L2) bilinguals. Children and adolescents attending bilingual schools within a L1 monolingual context completed a picture-naming task including cognates and non-cognates nouns, with collection of behavioral and ERP data. The study consistently found a cognate facilitation effect (CFE) in L2, evident in enhanced accuracy, faster reaction times, and reduced N400 negativity for cognates in comparison with no-cognate nouns. However, in L1, CFE was only observed in the N400 component, indicating weaker transfer from L2 to L1. Additionally, children exhibited greater N200 negativity when naming cognates in L1, while adolescents showed no N200 modulations, suggesting differences in frontal control region involvement and potential differences in control strategies. Language co-activation appears independent of maturation, while language control depends on development.