Augmentative and alternative communication, henceforth abbreviated as AAC, refers to communication methods -- usually at least somewhat technological rather than solely interpersonal -- used instead of or in addition to normal speech and language.

The most common AAC users are people who have one or some combination of motor, cognitive, and neurological impairments that get in the way of speech or language. Some examples of possible AAC users are:

People can come into AAC use as children, or have it introduced to them as adults. Some use it as a temporary bridge to learning or relearning speech, and others use it as their sole method of communication.

This writeup will be primarily an overview of the common kinds of AAC devices, along with common perspectives of AAC users and misconceptions about AAC.

Overview of AAC Devices

There are too many kinds of AAC devices out there to list fully. This is intended as an overview. An AAC user may use different devices in different situations: For instance, a text-to-speech synthesizer works well for long conversations, but a recorded-speech device or picture board is more efficient for short interactions. He may also use different devices at different periods in life -- a picture board might turn into an alphabet board as the user becomes literate. Someone whose friends can understand her "CP accent" but who can't make herself intelligible to strangers, might only use an AAC device around strangers.

It is worth noting that while Stephen Hawking can afford the most complicated gadgets out there, most of the rest of us make do with a combination of less expensive devices, and the old standby -- grunt and gesticulate.

Symbols Used

An AAC device uses any of a variety of symbols.

Alphabet: This is the most easily comprehensible set of symbols in literate societies. It may be arranged alphabetically, in a QWERTY or other common keyboard layout, in various adaptations for one-handed typing, and various layouts based on frequency of use. One of the biggest drawbacks is that you have to be able to read and write. The advantage is that you can easily create any word with it, including technical jargon, names, and made-up words. It's most suited to someone who is literate and has the motor skills to type effectively.

Words, Phrases, and Sentences: Some devices, instead of using individual letters, use words, phrases, and sentences that the user selects. The benefit is increased speed. The drawback, as with almost all of the systems that don't allow selection of individual letters, is decreased vocabulary.

Photographs: These are photographs of real objects, people, and concepts that the user wants to communicate about. They are ideal for someone who has difficulty comprehending the symbols in drawings, but can understand more concrete photographs of objects. A related concept is sculptures of the items in question, which can be useful for blind people.

Icons: These are stylized drawings of objects, people, and abstract concepts. Many have words written above or below them explaining the meaning of the icon. A person who isn't literate but can comprehend drawings and certain abstractions, or a person who finds pictures easier or faster than words, may use this system. Commonly used systems include PCS (Picture Communication Symbols), Makaton, and Rebus.

Alternate symbol systems: These combine either abstract or concrete symbols to form more complex concepts. They can be considered alternatives to the alphabet, and enable people with movement impairments to communicate more quickly than they could with letters. They are also useful for people with little to no functional literacy. A couple of examples:

  • Blissymbols. Developed by Charles K. Bliss and popularized in his 1949 book Semantography, this is an ideographic system that combines relatively few shapes to represent thousands of ideas. As an example, the word for teacher is formed by combining the symbols for person, container, up, and knowledge. Grammatical markers exist to differentiate things like parts of speech and tenses. Studies have shown that it works well for people with aphasia, but poorly for people with certain kinds of right hemisphere brain damage.
  • Minspeak. Developed more recently in order to speed the rate of communication for people with both speech and motor impairments, it combines concrete and familiar icons to form more complex concepts. For instance, umbrella + rainbow could mean rain, while heart + rainbow could mean happy, and rainbow + an object could mean the color of that object.
Selection Methods

There are several ways to select the symbols being used.

Direct selection refers to the user selecting the symbol directly with his or her body, rather than scanning. This can involve hands, feet, eyes, or sticks attached to the forehead or chin.

The most basic form of scanning is having another person say each option while the user stops him when he reaches the correct one. For instance, another person might say, "A, B, C, D" and the user might grunt or smile when the right letter is reached. This is, of course, tedious. A more high-tech version of scanning involves a communication grid with the rows and columns lighting up one by one. The user activates a switch when the correct row and column is reached. Scanning can be visual, auditory, or both. Scanning can be useful both for people with poor fine motor skills, and for people who need a prompt to remember what they were going to say.

A switch is a device an AAC user uses either in conjunction with scanning or because motor skills prevent using the device in the usual way. It can be anything from a button one presses to a motion-sensitive pad one waves one's hand (or other body part) over. A person might use a single switch, or multiple switches, to select items.

Kinds of Device

Many AAC users use several devices, combined with speech or a sign language. Others will use only one kind of device. As noted above, AAC can even involve using another human as the device, listing off choices or letters. Below are some of the common kinds of AAC device.

Communication boards are generally grids containing some combination of the preferred symbols. Made of wood, cardboard, paper, metal, or plastic, these are a low-tech AAC device. Depending on the symbols used, they might also be referred to as letterboards, alphabet boards, word boards, or picture boards. Eye gaze boards are transparent communication boards that communication partners sit on either side of. The AAC user can then look at the desired symbol in order to select it.

Communication books, wallets, and binders are much like communication boards. They have several pages, with one or more symbols or concepts to a page. They are relatively cheap and easy to construct.

Some people use single symbols on cards, which they hand to people in order to communicate.

Dedicated word processors and label makers have been used as simple high-tech communication aids, without voice output.

Simple text to speech synthesizers consist of a keyboard connected to a speech synthesizer. The device then speaks what the user types. One can also achieve this by running TTS software on a computer. Intelligibility varies greatly depending on the synthesizer.

Other devices use recorded speech. The user presses a button, switch, or set of buttons and switches to select a pre-recorded message. Such a device might have multiple "levels". This saves button space. For instance, a four-button device might store sixteen messages, with a button or switch to toggle between four levels. Each button will play one of four messages, depending on which level the device is set to.

Static-display devices have a display that may only be changed mechanically, if at all. For instance, the four-button device mentioned above might have a symbol on each button. In order to change the symbols, you have to take each symbol off of each button and replace them individually. Other static-display devices have paper or cardboard overlays, which allow a person to easily switch between grids or symbol-sets.

Dynamic-display devices have electronic displays that change easily with no mechanical assistance. This allows for features like branching categories: Pressing a symbol marked feelings might lead the user to a screen with symbols for happy, angry, scared, and sad. The user can use a touchscreen, keyboard, or switch to create a message. Common hardware for dynamic-display devices includes laptops, handhelds, tablets, and palmtops.

Dedicated AAC devices can only be used as AAC devices, while other AAC devices are modified computers that can run other programs.

The most complex high-tech AAC devices use dynamic displays and have a variety of symbol systems, as well as both synthesized and recorded speech. The text system generally has word prediction, abbreviation expansion, spell-checking, and a variety of other goodies. There is often an additional iconic symbol system, as well as areas to store anything from one-liners to speeches. The aforementioned Stephen Hawking has a relatively fancy AAC device.

Misconceptions and the AAC User Perspective

AAC users report a variety of problems interacting with the rest of society, few of which have to do with the person's disability.

As children, potential AAC users are often denied AAC because of a variety of misconceptions.

One is that a person has to demonstrate understanding of a communication system before she can use it. This is sort of like expecting a normal kid to talk without babbling first -- possible, but not likely.

Another is that using AAC will keep people from learning speech or language. In fact, AAC use, like other communication, enhances the communication skills of the user, may lead to later speech or literacy, and nearly always leads to better communication skills. A related idea is that someone who can speak to communicate basic needs doesn't need AAC. Most people want to be able to communicate a lot more than their basic needs.

Another particularly dangerous assumption is that people who don't speak and are extremely violent won't benefit from AAC, or even don't deserve AAC. In fact, violence is a brutal-but-effective method of communication for people who have no other way to communicate. Violence is the last refuge of the communicatively incompetent, and I've lived it. Given an AAC device and some training, a person might start pointing to "I'm hungry" instead of smashing things in frustration when his gut feels like it's gnawing itself to pieces. AAC, like spoken language, can mean freedom to communicate anything from basic needs like hunger to complex ideas like science and poetry.

People often assume that AAC users, and others who can't talk, automatically can't think, read, feel, have valid opinions, or make intellectual contributions. While all AAC users differ from each other in specific abilities, it is unfair to make such assumptions, and unfair to look down on those who can't do some of those things. Related is the idea that non-spoken communication is not "real" communication, which can lead to people ignoring the AAC user's carefully expressed thoughts. People often talk down to AAC users, as if they are children, or talk around them, as if they are objects.

Sometimes people refuse to wait for an AAC user to finish communicating, and cut him off in the middle of a sentence. AAC users who use speech synthesizers can run into trouble on the phone, where people will often believe they are answering machines, telemarketers, or prank callers. As with people with slow speech, other people might hang up on them before they can finish communicating.

AAC users' perspectives on good, well-chosen AAC devices are almost entirely positive. The inability to communicate one's thoughts and feelings can lead to frustration, depression, isolation, and loss of a sense of self-worth. One woman even became convinced, after years of difficulty communicating more than the most basic concepts, that she didn't have anything to say! Given time to get used to a system, it means communicative freedom, from which follow the ability to communicate one's own decisions and choices in life, and to pursue one's own goals -- not to mention the all-important ability to tell obnoxious people where to go.

Some of this knowledge is from extensive personal experience, and therefore unreferenced.


Fried-Oken, Melanie & Bersani, Hank A. Speaking Up and Spelling It Out: Personal Essays on Augmentative and Alternative Communication. Baltimore, MD: 2000.

Johnson, Roxanna M. The Picture Communication Symbols Guide. Solana Beach, CA: 1995.

Ace Centre. "Using Symbols."

Conti, Bob. "Minspeak FAQ's."

Marshall, Paul. "Blissymbolics."

Marshall, Paul. "Learning Bliss."

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