The purpose of the current study was to evaluate the ability of individuals with severe or global aphasia to identify and produce graphic symbols using a software program that turns a microcomputer into an electronic communication device. During the first phase of the treatment program, subjects were trained to identify single symbols and two-symbol combinations from different grammatical categories. The second phase involved training on production of simple subject-verb and subject-verb-object constructions using symbols correctly identified by subjects in the first phase. A single-subject, multiple-baseline design across behaviors replicated across five subjects was used to assess the effects of treatment on symbol identification. Results indicated that all subjects identified noun symbols with a greater degree of accuracy than symbols representing verb referents. Performance on symbol production task varied across subjects. The most frequently observed errors on the symbol production task were omission or incorrect selection of the symbols for the verb referents. Implications as to the efficacy of augmentative and alternative communication (AAC) systems for individuals with chronic severe aphasia are discussed.