title: Sign learning and profoundly retarded people.
mesh_terms: D000293:Adolescent; D000328:Adult; D004495:Education of Persons with Intellectual Disabilities; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007804:Language Development; D008297:Male; D008369:Manual Communication; D008875:Middle Aged; D012813:Sign Language