Augmentative and Alternative Communication and Autism


Voice Output Communication Aid

Augmentative and Alternative Communication (AAC) is any form of communication that people use if they are unable or unwilling to use standard forms of communication such as speech.

Augmentative communication systems are designed to complement and sometimes enhance standard means of communication.

Alternative communication systems are designed to replace standard means of communication.


There is evidence that the Picture Exchange Communication System may help some autistic children and adolescents to communicate more effectively. There is evidence that facilitated communication is not effective in supporting autistic people to communicate more effectively. Determining the benefits of the other forms of augmentative and alternative communication systems is not currently possible. We must wait for further research of sufficiently high quality to be completed

Risks and Safety

No risks are known for most forms of AAC. However, some significant risks exist for facilitated communication, including the danger of unsubstantiated claims of sexual abuse against family members of the autistic person.

Unaided AAC systems

Unaided augmentative and alternative communication systems includes various forms of communication that are used alongside or instead of spoken language and which do not require an external tool.

Unaided AAC systems includes facilitated communication, sign language, and total communication training.

More Information

Please see the section on Unaided AAC Systems

Aided AAC systems

Aided AAC systems use an external tool or device, electronic or otherwise. Aided AAC systems are sometimes split into low and high tech systems.

  • Low tech describes alternative and augmentative communication strategies which involve the use of equipment that is not electronic. Low tech AAC systems include communication boards and books, the Picture Exchange Communication System (PECS), picture-based AAC systems other than PECS.
  • High tech describes all electronic communication aids from single message switches to sophisticated, computer based communication systems that have many additional features. High tech AAC systems include mobile devices (such as cell phones and tablets) and voice output communication aids , also known as speech generating devices.

More Information

Please see the section on Aided AAC systems

Related Pages

Related Glossaries

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26 May 2022