With the growing popularity of dual immersion programs in schools and the widespread idea that language acquisition is something that needs to happen early in life, there is an age ideal for learning a second language (L2)?Wilder Penfield and Lamar Roberts first introduced the idea that there is a “critical period” for language learning in 1959. This critical period is a biologically determined period that refers to a period of time where learning/acquiring a language is relatively easy and generally met with a high degree of success. German linguist Eric Lenneberg further highlights Roberts and Penfield's findings and postulates the critical period hypothesis in 1967. According to the critical period hypothesis (CPH), certain biological events related to language development can only occur in the critical period. During this period, the brain possesses a certain degree of flexibility (ability and ease of learning a language) and lateralizes (the assignment of linguistic functions becomes concrete – both in the left and right hemisphere) (Marinova-Todd, S ; Marshall, D & Neve, C. 2000 9-10). This critical period lasts from childhood until the onset of puberty (usually around age 12). Once this period is over, it is more difficult to learn a language because the language functions in the brain have become concrete. This hypothesis can be seen in the case of Genie, a woman who was isolated from human interaction and language until the age of 13. When she was rescued, she was past the critical period for language acquisition and, as such, did not have full command of the English language. If she had been saved before the age of 13, she might have had greater language skills. However, this explains that the first… middle of the paper… of the L2, can actually lower their affective filters. All in all, there is no ideal age to learn a second language. It all depends on the individual and their circumstances. Works Cited Brown, H. (2000). Principles of language learning and teaching. 4th edition. New York: Pearson Krashen, S. D. (1982). Principles and practice in second language acquisition. Prentice Hall International pp. 13-14, 29-30 Marinova-Todd, S., Marshall, D., Snow, C. (2001). Three misconceptions about age and L2 learning. TESOL Quarterly, Vol. 34, no. 1. TESOL Inc pp. 9-10, 25-27Schouten, A. (2009). The critical period hypothesis: Support, challenge, and reconceptualization. Working Papers in TESOL and Applied Linguistics Vol. 9, no. 1 pp. 3-4Zhang, C. (2009). A study on the influence of age on L2 acquisition. Asian Social Sciences Vol.5, No. 5. pp. 133-135