We assessed the effects of two computer systems used as microswitches for the vocal utterances of an adolescent and a young adult with multiple disabilities. The systems were to respond to three one-syllable utterances of the first participant and nine word-like utterances of the second participant by presenting favorite stimuli linked to those utterances. The computer system used for the first participant relied on a software program developed specifically for this study. The computer system used for the second participant combined a new software program with a commercially available speech recognition program. Results showed that both participants increased the frequencies of their target utterances and obtained high levels of stimulation. Positive performance was maintained at post-intervention checks. Technical and practical implications of the data are discussed.