“…Normally, either can be expected to be very damaging. Lenneberg (1967), for example, who postulated a sensitive period for learning language, argued that normal language acquisition depends on normal language experience between approximately 2 and 14 years of age; yet startling contradictory examples, such as Kaspar Hauser in Nuremberg, Germany, who acquired language after the age of 17 years (Simon, 1979) and Genie in California who began to acquire language after the age of approximately 14 years (Curtiss, 1977), cast genuine doubt on the strong form of Lenneberg's hypothesis (see Snow, 1987). That effects of a sensitive period are not fixed need not, however, undermine the notion of the sensitive period, so long as something special for development from that period remains.…”