Prader-Willi syndrome was initially identified in 1956. Since then, a majority of the literature pertaining to Prader-Willi has focused on the medical and genetic aspects of the syndrome. There has been limited information available regarding the speech and language abilities of children with Prader-Willi. This study investigated the communicative development of 18 children with the syndrome, ranging in age from 8:8 to 17:1. A number of evaluative procedures were used to evaluate the subjects' spontaneous speech, articulation, and receptive and expressive language abilities, as well as their voice, fluency, oral mechanisms, hearing, and their developmental histories. A variety of communicative deficiencies were found in the children's speech, language, voice, and fluency.