FIRST-LANGUAGE ACQUISITION IN ADOLESCENCE - EVIDENCE FOR A CRITICAL PERIOD FOR VERBAL LANGUAGE-DEVELOPMENT

It has been hypothesized that there is a critical period for first-lan guage acquisition that extends into late childhood and possibly until puberty. The hypothesis is difficult to test directly because cases of linguistic deprivation during childhood are fortunately rare. We pres ent here the case of E.M., a young man who has been profoundly deaf si nce birth and grew up in a rural area where he received no formal educ ation and had no contact with the deaf community. At the age of 15, E. M. was fitted with hearing aids that corrected his hearing loss to 35 dB, and he began to learn verbal Spanish. We describe his language dev elopment over the 4-year period since his acquisition of hearing aids and conclude that he demonstrates severe deficits in verbal comprehens ion and production that support the critical period hypothesis. (C) 19 98 Academic Press.