The splendid review provided by Mayberry and Kluender (2017) confirms Lenneberg's 1967 hypothesis that a Critical Period (CP) exists for the establishment of a native language. However, Lenneberg's extension of the CP hypothesis to the later learning of an L2, based on his observation that most individuals who learn an L2 after about the age of 13 speak it with a foreign accent (FA), is doubtful.