Dawn

What is AAC?

AAC stands for augmentative and alternative communication. It covers every way of communicating that adds to speech or stands in for it, from pointing at a picture to an app that speaks what you type.

By the Dawn AAC team · Updated · 2 minute read
Not yet reviewed by a speech-language pathologist. How we write these guides.

What does AAC mean?

"Augmentative" means adding to speech. "Alternative" means used instead of speech. ASHA, the US professional body for speech-language pathologists, describes AAC as supporting or compensating for difficulties with speaking and with language.1

For people who can't rely on speech, AAC is the main way they communicate.

What kinds of AAC are there?

AAC is often split two ways.1

  • Unaided AACNothing extra is needed: gestures, facial expressions, signs, body language.
  • Aided AACSomething outside the body is used: a picture board, a letter board, a notebook, a tablet or a phone.
  • Low-tech aided AACDoesn't need power: printed symbol boards, alphabet boards, pen and paper. Useful as a backup and in places a device can't go.
  • High-tech aided AACUses electronics, usually with speech: dedicated speech devices and apps on tablets and phones. These are often called speech-generating devices.

High-tech AAC apps usually offer some mix of three ways to build a message: tapping symbols (pictures with words), typing, and choosing whole phrases that have been saved in advance.

A symbol-based AAC board in Dawn with columns of words such as I, want, go, more, not, yes and what
A symbol board: each button is a word with a picture. Tapping words builds a sentence in the bar at the top.

Who uses AAC?

People of all ages. Some are born with a condition that affects speech, such as autism, cerebral palsy, Down syndrome or childhood apraxia of speech. Others lose speech later, through a stroke, ALS (MND), Parkinson's, multiple sclerosis, a brain injury or cancer surgery. Some need AAC for a short time, after an operation or while on a breathing tube.

A UK study estimated that about 1 in 200 people could benefit from AAC.2 A textbook gives estimates of 5 million people in the US and 97 million worldwide; those figures are estimates, not counts from one study.3

Why does speed matter?

People usually speak at somewhere between 125 and 185 words a minute. Communicating with aided AAC is much slower: around 8 to 10 words a minute when pointing directly at buttons, and as little as 2 words a minute when scanning with a switch.4 Pauses of more than about three seconds can make it harder to take a turn in conversation.4

Saved phrases, word prediction and a voice that starts speaking without a delay all help close some of that gap. In research on whole-phrase AAC, faster conversation went together with listeners judging the AAC user as a more competent communicator.5

Does the voice matter?

For years, many AAC users had a choice of only a few synthetic voices, often not matching their age, gender or accent. In an older study from 1989, using the synthetic voices of the time, girls and women judged only natural female voices acceptable as a stand-in for their own.6 In a 2024 study, 831 listeners rated newer voices made with neural networks as clearer and more natural than older synthetic voices, and preferred them.7

People who are losing their speech can also record their own voice to use later. See recording your voice for later use.

Dawn for iPhone and iPad

Dawn is an AAC app for iPhone and iPad. You can tap symbols, type messages, or play saved phrases and recordings.

Questions people ask

Is AAC only for people who can't speak at all?

No. Many people who use AAC have some speech. They use AAC when speech is slow, unclear, tiring or not working that day. ASHA describes AAC as something that supplements speech as well as replacing it.1

Is sign language AAC?

Signs and gestures used to support or replace speech are a kind of AAC called unaided AAC, because they don't need any equipment. Full sign languages, such as American Sign Language or British Sign Language, are languages in their own right, used by Deaf communities.

What's the difference between AAC and a speech-generating device?

A speech-generating device is one kind of AAC: equipment that speaks out loud. It can be a dedicated device or an app on a tablet or phone. AAC also includes things that don't speak, like picture boards, letter boards and writing.

Who decides which AAC someone should use?

The person and the people close to them, ideally with help from a speech-language pathologist (a speech and language therapist in the UK). Many people end up using several kinds: an app for most things, a letter board for the shower, gestures with family.

Sources

  1. American Speech-Language-Hearing Association. Augmentative and Alternative Communication (Practice Portal). www.asha.org/practice-portal/professional-issues/augmentative-and-alternative-communication
  2. Creer S, Enderby P, Judge S, John A. Prevalence of people who could benefit from augmentative and alternative communication (AAC) in the UK: determining the need. International Journal of Language & Communication Disorders, 2016. doi.org/10.1111/1460-6984.12235
  3. Beukelman DR, Light JC. Augmentative and Alternative Communication: Supporting Children and Adults with Complex Communication Needs, 5th edition. Paul H. Brookes, 2020 (chapter 1 excerpt). brookespublishing.com/wp-content/uploads/2020/02/Beukelman-Excerpt-wTOC.pdf
  4. Waller A. Telling tales: unlocking the potential of AAC technologies. International Journal of Language & Communication Disorders, 2019. pmc.ncbi.nlm.nih.gov/articles/PMC6491981
  5. Todman J, Alm N, Higginbotham J, File P. Whole utterance approaches in AAC. Augmentative and Alternative Communication, 2008. doi.org/10.1080/08990220802388271
  6. Mirenda P, Eicher D, Beukelman DR. Synthetic and natural speech preferences of male and female listeners in four age groups. Journal of Speech and Hearing Research, 1989. doi.org/10.1044/jshr.3201.175
  7. Hyppa-Martin J, et al. A large-scale comparison of two voice synthesis techniques on intelligibility, naturalness, preferences, and attitudes toward voices banked by individuals with ALS. Augmentative and Alternative Communication, 2024. doi.org/10.1080/07434618.2023.2262032
  • Does AAC delay speech?Findings from studies of AAC and children's speech, from toddlers to teens.
  • How to start AACSetting up AAC and using it with your child in the first few weeks.
  • Choosing an AAC appWhat to check when choosing an AAC app: word layout, voice, access, offline use, privacy and trials.
  • Who Dawn is forEvery condition and situation, from autistic children to ALS.

Try Dawn on iPhone or iPad

Symbols, typing and saved phrases, spoken in a natural voice. Dawn can also build a voice from about eight seconds of your own speech.

Requires iOS 17 or later.