The paper examines the use of the Makaton Vocabulary, a language program designed to provide a controlled method of teaching approximately 350 signs from British Sign Language with speech, to mentally handicapped and other language handicapped persons. The approach stresses two-way functional communcation using a core of basic words. Extension of the program to other types of disorders is noted, and success is claimed in terms of language and concept development as well as in increased eye contact, attention, and sociability. Observations about possible reasons for the success of the Makaton approach are suggested. Appendixes list the Makaton Vocabulary, and chart and list the organization for the Makaton Vocabulary Development Project. (CL)