Contextual Linguistic Diversity Can Affect Executive Function in Multilingual Malaysians

The relationship between multilingualism and executive function remains debated, with most studies evaluating mono-bilingualism dichotomously and taking place in Western societies. In contrast, our research is situated in Malaysia, which presents a context of rich sociolinguistic diversity and an (almost) ubiquitously multilingual population. We examine the variation of contextual linguistic diversity (CLD; diversity of language exposure at the societal level) and language entropy (diversity of individual language exposure) for Malaysian adults, and explore the link between their CLD, language entropy, and executive function. One hundred and four participants completed (at least one of) three low-verbal cognitive tasks that tap into inhibitory control (flanker task), working memory (2-back task), and task switching skills (set-shifting task). Results show that while almost all participants are multilingual, there was substantial individual variation in CLD and language entropy, highlighting the importance of considering such measures when studying multilingualism. Crucially, CLD significantly predicts performance in some cognitive tasks: higher CLD is associated with less interference in switching and potentially also with better working memory, illustrating an interplay between context and cognition. This study suggests that different degrees of CLD can modulate cognitive performance even within a highly multilingual population.