Abstract
This research paper is a review of the previous literature that focuses on whether or not there is an influence of second language acquisition during 'critical period'. Critical period refers to acquiring a second language before the age of adulthood. Although there is no consensus among linguists on the impact of the critical period, numerous scholars in the field of second language acquisition agree that language learners gain more benefits during the critical period including mastering the phonological system of the target language. In addition, this paper compares between the potential linguistic benefits between young learners who acquire language at an early age of their lives and their older counterparts who begin learning a language after the age of maturation. Interestingly, those who start studying a second language during the critical period usually outperform their older counterparts due to their exceptional memory traits and fresh speech organs ultimately, it displays the appropriate teaching approaches based on age benefiting from the idea of critical period hypothesis.