This case study describes the processes of functional analysis and modality assessment that were utilized to design a communication intervention for an adolescent with autism who engaged in loud and disruptive vocalizations for most of the school day. The functional analysis suggested that the vocalizations served both tangible and escape functions. The modality assessment suggested that the participant could use a speech-generating device to make requests for a preferred item. Results of the intervention suggested that functional communication training was useful in decreasing the frequency of vocalizations and increasing independent requesting in school and community settings. The results are discussed with regard to their implications for the treatment of stereotypic vocalizations and the limitations of the case study design. We also discuss the importance of international educational efforts related to the dissemination of evidence-based practices such as functional analysis and functional communication training. (Contains 2 figures.)