title: Impacts of learning american indian sign language on mentally retarded children: a preliminary report.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004495:Education of Persons with Intellectual Disabilities; D006801:Humans; D007198:Indians, North American; D008369:Manual Communication; D012813:Sign Language; D014705:Verbal Behavior