This project has two interrelated goals. The first objective is to achieve a better understanding of the positive cognitive consequences of life long bilingualism, specifically in the domain of executive function. To this end, the performance of monolingual English and bilingual Hebrew-English speakers will be compared on several variants of the task-switching paradigm, sensitive to different manifestations of inhibitory control and mental shifting. The second objective is to explore whether these same cognitive skills of inhibitory control and mental shifting have predictive value in understanding individual differences in instructed foreign language outcomes. The guiding principle is that skills that are important for managing the fluent use of two languages might also confer an advantage in the process of language learning. Therefore, the English proficiency of native Hebrew speaking language learners will be assessed, and the utility of using inhibitory control and mental shifting abilities as predictors of language learning outcomes will be investigated. Research carried under the first objective can make the following contributions to state-of-the-art knowledge: 1) further our understanding of the consequences of bilingualism, which can impact language policy and planning from the individual to the national level; 2) provide evidence for the manner in which life experience can shape cognitive functions; 3) inform the debate contrasting modular language abilities versus reliance on domain-general cognitive processes. Research fulfilling the second objective: 4) will expand current models of the cognitive underpinnings leading to successful foreign language learning; 5) may ultimately shape the pedagogy of foreign language instruction.