This study investigated whether differences in executive control exist between bilinguals and monolinguals who share a dual-language context. We compared functional monolingual and bilingual groups’ cognitive performance and the correlation between self-reported and objective linguistic variables and cognitive outcomes. Group comparisons revealed no significant differences between functional monolinguals and bilinguals on inhibition, task switching and updating of information. However, distinct correlational patterns were observed within groups. In functional monolinguals, participants with lower bilingualism scores showed better task-specific inhibition (Color–Word part of the Stroop task) and a better ability to monitor for conflicts (Digits Forward task). In contrast, bilinguals with higher degrees of bilingualism showed better overall inhibition outcomes (Stroop effect). Findings are discussed in terms of the importance of adopting more comprehensive methodological approaches to study bilingualism as a heterogeneous phenomenon, considering the diversity within each group and the cultural and linguistic context in which the bilingual experience takes place.