A Voice Output Communication Aid, or VOCA, is a device that provides text-to-speech (TTS) or picture-to-speech capabilities for individuals who have difficultly producing speech themselves.  VOCAs are a form of Augmentative and Alternative Communication (AAC), a class of communication strategies that also includes sign language, gesturing, and use of symbols to communicate non-verbally. Nearly half of the total population of autistic individuals is thought to be "non-verbal," and all of these people may benefit from the use of a VOCA device that they can carry on their person and utilize to communicate with others.

Existing VOCAs may be expensive, hard to use, or difficult to carry.  Professor Rosalind Picard, Joel Smith, and Amanda Baggs recently wrote a whitepaper (download in PDF format) about the limitations of existing VOCA devices based on interviews with current VOCA users and those familiar with some of the VOCA devices that are used by autistic adults.  This inspired us to create this wiki to enable the development of new and improved VOCAs using existing hardware and software tools that can be mixed, matched, and customized in creative ways.