What is AAC
Augmentative and alternative communication (AAC) refers to communication tools and techniques used to supplement communication for people who have difficulty communicating through speech or writing.
AAC includes unaided communication techniques (e.g. pointing, gestures), low technology (e.g., communication books and boards) and high technology AAC (e.g., devices and computers that have voice output).
Adapted from: International Society of Augmentative and Alternative Communication, http://www.isaac-online.org/en/aac/what_is.html