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Introduction to AAC (Augmentative and Alternative Communication)

"AAC is used by people who, some or all of the time, cannot rely on their speech. AAC incorporates the individual's full communication abilities and may include any existing speech or vocalizations, gestures, manual signs, and aided communication. AAC is truly multimodal, permitting individuals to use every mode possible to communicate. Over time, the use of AAC may change, although sometimes very slowly, and the AAC systems chosen today may not be the best systems tomorrow.

By recent estimates, well over 2 million persons who present with significant expressive language impairment use AAC. AAC users encounter difficulty communicating via speech due to congenital and/or acquired disabilities occurring across the lifespan. These conditions include but are not limited to autism, cerebral palsy, dual sensory impairments, genetic syndromes, intellectual disability, multiple disabilities, hearing impairment, disease, stroke, and head injury.

Bottom Line: Augmentative and alternative communication (AAC) describes multiple ways to communicate that can supplement or compensate (either temporarily or permanently) for the impairment and disability patterns of individuals with severe expressive communication disorders.

Unaided Versus Aided Communication

Typically, AAC includes unaided and aided modes of communication.

Unaided modes of communication include non-spoken means of natural communication (including gestures and facial expressions) as well as manual signs and American Sign Language (ASL). These modes of communication often require adequate motor control and communication partners who can interpret the intended message.

Aided modes of communication include those approaches that require some form of external support, such as a communication boards with symbols (e.g., objects, pictures, photographs, line drawings, visual-graphic symbols, printed words, traditional orthography) or computers, handheld devices, or tablet devices with symbols that generate speech through synthetically produced or recorded natural (digitized) means.

For individuals with severe disabilities, it can be helpful to encourage (and teach) both unaided and aided modes of communication. Individuals may need to be taught when it is appropriate to use different modes of communication. For example, the individual may sign when interacting with parents at home but may use a picture-based system or speech generating device (SGD) with other communication partners. Individuals with very complex needs and a limited communication repertoire can learn to use different systems in different contexts.

Bottom Line: AAC can involve unaided communication, such as facial expression, body posture, gesture, or sign language, and aided modes (e.g., communication books, tablets). The appropriate mode or modes of communication are determined by the needs of the individual with disabilities and their communication partners.

Decision Making About AAC Systems and Interventions

The currently accepted evidence suggests that there are no specific prerequisites (e.g., age, cognitive, linguistic, motor) for getting started with AAC. A number of AAC options are available to begin the intervention process. Ideally, the decision to introduce AAC should be made in consultation with the consumer, family, and a team of professionals. However, no individual should go without communication, and all individuals should have access to AAC systems that promote effective communication.

AAC should also be considered for individuals who have some speech or speech that is unintelligible to unfamiliar listeners. These individuals may use AAC to augment their communication. Other individuals may use speech in low-demand contexts but choose to use AAC to augment their communication in high-demand contexts. The presence of speech should not preclude the consideration of AAC as a support.

Decisions When Choosing Aided AAC

Choosing an aided AAC system requires careful consideration of an individual’s current skills, strengths, and needs, but it is important not to restrict the individual’s potential. Assessment strategies can lead to an understanding of:

  • Options for different symbols, systems, and access modes

  • The contexts where the individual must communicate

  • The skills and supports available to partners

  • The profile of the individual including: vision, hearing, sensory-motor, motivation, cognitive, linguistic, literacy skills, and current modes of communication

Dynamic assessment processes allow for this to happen while individuals are learning.

Bottom Line: Choosing aided AAC is a critical, discerning process that involves the ongoing consideration of multiple factors."

Article created by:

American Speech-Language-Hearing Association. (n.d.). Augmentative and alternative COMMUNICATION (AAC). American Speech-Language-Hearing Association.


Beukelman, D. & Mirenda, P. (2013). Augmentative and Alternative Communication: Supporting Children & Adults with Complex Communication Needs 4th Edition. Baltimore: Paul H. Brookes Publishing.

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