Many linguists believe that there is a limited period of time in which language acqusition can occur. This is known as the"Critical period Hypothesis." This period is thought to lasts from birth until around the age of 12 or puberty. Many linguists believe that if kno language at all is learned during this period, it will never be learned in a normal or fully functional sense and that though language*can be learned to perfection after this period, it will be on the syntactic level and speakers exhibit marked performance deficits in the language, most notably the lack of a native-like accent.