This case study focused on skill generalization following instruction of an adolescent girl with multiple disabilities using two augmentative and alternative communication (AAC) devices: a simple pictographic display and a voice output communication aid (VOCA) with an identical display used as an overlay. An alternating treatments design was used to assess community members' response latency, focus of attention, and comprehension of requests made via the two AAC devices. Skill generalization occurred for both devices, with similar rates of efficiency. These findings underscore the importance of the use of multiple modalities and of incorporating individual preferences to enhance the communicative competence of individuals who use AAC in natural environments.