Children with complex communication needs (CCN) resulting from autism spectrum disorders, cerebral palsy, Down syndrome and other disabilities are severely restricted in their participation in educational, vocational, family, and community environments. There is a substantial body of research that demonstrates convincingly that children with CCN derive substantial benefits from augmentative and alternative communication (AAC) in their development of communication, language and literacy skills, with no risk to their speech development. Future research must address two significant challenges in order to maximize outcomes for children with CCN: (1) investigating how to improve the design of AAC apps/technologies so as to better meet the breadth of communication needs for the diverse population of children with CCN; and (2) ensuring the effective translation of these evidence-based AAC interventions to the everyday lives of children with CCN so that the "possible" becomes the "probable." This article considers each of these challenges in turn, summarizing the state of the science as well as directions for future research and development. (Contains 1 figure.)