Establishment of symbolic communication in persons with severe retardation.

For persons with severe retardation, learning to communicate symbolically is a complex long-term process requiring the coordination of many components to succeed. Three of four institutionalized adolescents and young adults with severe retardation who participated in this study learned to use lexigrams to request foods and, subsequently, objects. Although their request skill did not initially generalize to labeling and to comprehension tasks, additional request experience with lexigrams resulted in consistent improvement in performance in both tasks. The emergence of subject-initiated lexigram communications and the facilitation of spoken language comprehension and/or production were also observed.