Contingent social reinforcement was applied differentially to aid the behavioral and educational development of a 9-year-old severely retarded nonverbal female with quadriplegic spastic cerebral palsy. Four behaviors prerequisite and collateral to beginning language development were defined and measured: eye contact, head control, initiative vocalization, and drooling. Non-professional staff who had contact with the child were trained in the differential application of contingent positive social reinforcement. Treatment was administered in multiple baseline design, and improvements in all behaviors were observed over the 20 week program and during a 1 month followup period. (Author/CL)