Augmentative and alternative communication

Augmentative and alternative communication (AAC) encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production or comprehension of spoken or written language. AAC is used by those with a wide range of speech and language impairments, including developmental disabilities such as cerebral palsy, intellectual disability and autism, and acquired conditions such as amyotrophic lateral sclerosis and Parkinson's disease.

Source: Wikipedia — Augmentative and alternative communication (CC BY-SA 4.0)