The effectiveness of sign language was compared with verbal language instruction with 12 nonverbal severely retarded students (4 to 9 years old). Ss received either speech training, sign language training, or instruction in an area other than communication. During the second year, 10 Ss received training from their parents. Results indicated no significant differences between the three groups (sign language, speech, and placebo) for the total number of words learned or the linguistic level achieved, nor were there significant correlations among Ss' cognitive level and their learning of either sign language or verbal language skills. The hypothesis that Ss in the sign language condition would learn more words than SS in the speech training condition was statistically rejected, although all four signing condition Ss learned some signs while only two of the speech condition Ss learned to say any words. (CL)