Referential communication skills of moderately mentally retarded adolescents (20 speaker/listener dyads with a mean age of 15.75 years) were investigated. In Study 1, S performance on referential communication activities (divided into three skill levels) was examined. Degree of idiosyncratic messages communicated was investigated in Study 2. Listening competence of retarded and adult listeners was compared in Study 3. (Author/PHR)