Teaching interactive signing in a dialogue situation to mentally retarded individuals.

Verbal prompts, modeling, physical guidance, positive reinforcement, fading, and chaining procedures were used to teach two nonverbal individuals, one severely and one moderately mentally retarded, an interactive signing dialogue in a naturalistic snack time setting. Both were required to initiate signed communication and to respond to signed communication with either action or manual signing. Using a multiple probe design across three dialogue situations, each client was successively taught his role in each dialogue with a staff member serving as his partner.