The relationship between cognitive control and second language proficiency

In the past 20 years, the field of bilingualism has made a substantial effort to better understand the set of cognitive mechanisms that allow bilinguals to functionally manage and use their languages. Among the mechanisms that have been identified, cognitive control has been posited to be key for proficient bilingual language processing and use. However, the role of cognitive control in developing bilingualism, i.e., among adult learners learning a second language (L2), is still unclear with some studies indicating a relationship between cognitive control and adult L2 development/developing bilingualism and other studies finding the opposite pattern. This set of contradictory findings merits further investigation in order to deepen our understanding of the role that cognitive control plays during the process of becoming bilingual. In the present study, we aimed to address this open question by examining the role of cognitive control among adult L2 learners of Spanish at the intermediate level using multiple behavioral measures as a way to provide a multidimensional perspective on the role of cognitive control and developing bilingualism. Our results indicate a significant relationship between cognitive control abilities, specific to reactive control, and overall L2 proficiency. We also found a significant relationship between speed of processing and overall L2 proficiency. The results of this study contribute to the existing body of knowledge on cognitive factors related to developing bilingualism and provide critical new insight into the underlying cognitive mechanisms that may contribute to adult L2 learners becoming bilingual