Cognitive effects of bilingualism: Executive functions and language practice

Previous studies with bilinguals suggest that bilinguals' long time practice of two languages provides them with cognitive advantages. Results from empirical studies also have shown consistent evidence of bilinguals' cognitive advantages on their executive functions (EFs). However, most studies of EFs have focused on cognitive differences between monolinguals and balanced bilinguals and those studies failed to provide a detailed description of how bilinguals practice dual languages even though they suggested that bilinguals' cognitive benefits resulted from their continuous language practice. Additionally, if using two languages yield cognitive benefits, it is highly possible to expect a certain degree of cognitive advantages in bilinguals with intermediate L2 proficiency who have relatively short time practice of bilingualism in comparison with bilinguals with high L2 proficiency. However, not many studies have been done with bilinguals with intermediate L2 proficiency who are in the process of becoming bilinguals with high L2 proficiency. The current study had three purposes: 1) The first purpose was to examine possible cognitive differences in executive functions (EFs) among three language groups: a young adult Korean near-monolingual group and two young adult Korean-English bilingual groups with different levels of language proficiencies. Specifically, it investigated how the different proficiency levels of bilingualism affected the EFs of the two bilingual groups. 2) The second purpose of the study was to explore how bilinguals in each group practiced their dual languages in everyday life, especially in relation to possible cognitive efforts that they placed on using their L1 and L2. 3) The third purpose was to explore the relationship between bilinguals' possible cognitive differences and their daily language practices.;The parallel mixed method design (Teddlie & Tashakkori, 2009) was employed in order to accomplish the goals of the study. Three components of EFs were tested through a cognitive test battery including: 1) the Simon Task (ST) to measure component, inhibitory control, 2) the Wisconsin Card Sorting Test (WCST) to measure cognitive flexibility, and 3) the Digital Span Task (DST) and the Corsi Block-Tapping Test (CBTT) to measure Working Memory (WM). The tests were conducted on three different language groups: 20 Korean near-Monolinguals and 20 Korean-English Intermediate Bilinguals and 20 High Bilingual groups. Bilinguals' daily language practice was explored through semi-structured interviews with four bilinguals from each of the bilingual groups. The convergence of the findings from two cognitive tests and interview data suggested that the bilinguals' efforts in learning and processing their second language (L2) served as a continuous mental training and enhanced bilinguals' cognitive functions; however, the advantages relied on how they practiced their languages, not solely from the fact that they knew and used both languages.