The purpose of this study was to examine the effects of Functional Communication Training (FCT) and a Voice Output Communication Aid (VOCA) on the challenging behavior and language development of a 4-year-old girl with autism spectrum disorder. The participant's mother implemented modified functional analysis (FA) and intervention procedures in Kerri's home. A multiple probe design across activities was used to analyze intervention effectiveness. FCT with a VOCA successfully decreased Kerri's challenging behavior and increased VOCA use. A secondary analysis revealed that Kerri increased her use of correct pronouns. Kerri's mother implemented modified FA and intervention procedures with a high level of fidelity. Social validity data indicated that Kerri's mother believed the intervention to be acceptable and effective.