Cognitive Performance in the Dominant Language: A Comparison of Bilingual and Monolingual Adults on Executive and Lexical Tasks

Purpose: This study examines the effects of bilingual experience and age of acquisition on executive control and lexical performance in the dominant language. A total of 23 adults participated, including early bilinguals (Kurdish/Arabic–Turkish), late bilinguals (Turkish–English), and Turkish monolinguals. Method: Participants completed a color-naming Stroop task to assess inhibitory control and a vocabulary task in Turkish to measure lexical retrieval. Findings: Non-parametric analyses revealed that early bilinguals significantly outperformed both late bilinguals and monolinguals in the incongruent condition of the Stroop task, indicating enhanced executive control. In contrast, no significant differences were found among the three groups in vocabulary performance in Turkish. Conclusion: These findings suggest that early and sustained bilingual exposure may confer advantages in executive functioning, whereas lexical performance in the dominant language appears less sensitive to bilingual experience under conditions of similar language exposure. The study highlights the critical role of age of acquisition and language exposure in shaping cognitive outcomes of bilingualism, while also underscoring the need for further research with larger samples and multiple measures.