top of page


Alternative and/or

Augmentative Communication

AAC (Alternative and/or Alternative Communication) is the term that we use to refer to communication that supplements ('augmentative') or replaces ('alternative') oral communication. People who have difficulty transmitting their meaning to their communicative partners because of speech, language and/or hearing problems use AAC to more effectively transmit their meaning. AAC is also used to teach children who do not have control over oral communication, or who have language-learning impairments, to learn language.


There are various ways in which a person can learn to communicate that will augment (supplement) the communication that they already have, and/or which will give a way of communicating that is unlike typical oral spoken communication (i.e alternative).

Systems can be “aided” or “unaided”:

"Non-aided” systems usually involve the person’s body being used to communicate. Non-aided systems include gestures, pointing, eye gaze, facial expressions, the various sign languages of the world, Makaton™ , and baby signing.

"Aided” systems  involve the use of something other than the person’s body. These systems are  either electronic or paper-based. Electronic systems include things like tablets with apps, or systems designed by AAC companies that are dedicated devices that talk for a person. Paper-based systems include things like communication books which contain pictures that the person chooses to communicate something. 

Aided systems can be “high tech” such as using computers or can be “low tech” such as communication books.

Low-tech systems include paper, 3D symbols, communication books with per-prepared symbols and/or words, paper and pen.

High-tech systems include laptops, specially designed machines, 'speech generating devices' and so on.

Like oral language, AAC systems are usually symbol-based.

Oral spoken language is a symbolic system: the words we use represent meaning and are therefore symbols. So, for example, the word "dog" represents the four-legged animal that barks, and we can use the word to talk about a four-legged animal that barks even if we cannot see it. No matter which context we are in, we all know what we mean when we talk of a 'dog'. Gestures are symbols too  - e.g. a nod represents "yes".

Most AAC systems comprise symbols. The choice of symbol depends on the sensory, physical, and cognitive skill of the person. A person can only use a symbol-based system if he or she has - or learns - to symbolise.


AAC systems use different types of symbols, and sometimes combine symbols (e.g. a picture and a word):

  • 3-D representations (e.g. a bar of soap representing 'washing'; a toy car representing 'go in the car', a cup representing  'drink')

  • tactile symbols (e.g. a piece of fabric representing' clothes'; a piece of sandpaper representing 'outside')

  • photographs

  • colour pictures

  • line drawings

  • specially designed systems such as Braille (for the blind) and some dedicated communication symbol systems

  • the written word.

There are a number of programmes that have specially designed symbols for use in AAC such as Boardmaker ™ ,Symbolstix™, Picture Communication Symbols (PCS) ™, Widgit Symbols™,  and Blissymbols™. These systems are researched and are used internationally.


There are also graphic symbol systems associated with specific high-tech communication aids, e.g. Minsymbols™ and Dynasyms™.  


Different hardware and software use different programmes, and one has to choose a programme that best suits a particular client.

Some systems use speech generation.


AAC systems that use speech generation are known as VOCAs (Voice Output Communication Aids) or SGAs (Speech Generating Devices). SGDs are available in various shapes and sizes. They all have an in-built system that allows the device to produce speech. The various devices come with built-in synthesised voices and today, a variety of 'voices' are available so we can match the person who uses the AAC device to a voice. Many SGDs also have the ability to record speech.


The idea is that the user selects a symbol or set of symbols, and the machine either speaks a pre-recorded message (a digital message), or the person using the device generates a message that the machine then speaks (a synthesised message). (Digitised speech is prerecorded human speech. Synthesised speech is computer generated).

SGDs can produce very simple messages or very complex messages and everything in-between:

Single message SGDs: A single message is recorded and spoken. Usually one can change the message whenever required.

Message Sequencer SGDs: These devices record a number of messages in a sequence.

The symbols are presented in different ways:

Overlay SGDs:  Overlays with pictures, symbols or words are placed are placed over the keys. The use presses or touches one of these symbols to choose which message should be spoken. 

Dynamic Screen SGDs : These devices display symbols or graphics on a screen rather than on paper overlays.

Dedicated and non-dedicated AAC devices

Some SGDs are dedicated AAC devices, made by companies such as Tobii Dynavox , Prentke Romich,  and Saltillo. Today, AAC is available for many of the day-to-day electronic devices that we use such as smart phones, laptops and tablets. It is really a matter of choosing what is affordable and appropriate for the individual user. I also stress that whichever route you go, you have to ensure that you have access to back up and support locally. Most importantly is that the features of an AAC system match the needs of the user.


We usually recommend that if a device such as a tablet is to be used for AAC, that it is only used for AAC. If an AAC app is used intermittently and the individual is not dependent on it for communication, it can be used for other purposes as well. An individual who uses the AAC device to communicate at all times should not use it to play on as well, - and  nobody else should use it for any other purpose either! - because the communication system is not readily available to the person who needs it to communicate.


Today, much of the software can be used on multiple devices.

For families who are not strict about ensuring that a device is only used for communication and who do not make sure that it is accessible to the user at all times, I prefer to recommend dedicated AAC devices that cannot be used for any other purpose.

Access methods

'Access methods' is the term that we use to refer to the  various ways that a person who uses AAC can access  and control an AAC device. Many people who require the use of AAC have physical limitations. For example, a person may not be able to press an icon on a tablet, or may not be able to press one button on a keyboard. There are wonderful adaptations available today that make it possible to be able to use AAC using a movements such as a foot movement, eye-gaze or a blink, and even a puff of air.

  • Eye gaze systems: In order to select a symbol on a device, the person using the device looks at the required item on the screen and then selects that item by either pressing a switch or holding their gaze for a pre-set length of time.

  • Simple switches are activated by pressing down on the top with some part of the body (e.g. hand, head, knee). Switches are available in different sizes, shapes and colours. Some switches are available to accommodate for people who require the slightest amount of pressure.  Some people cannot activate switches reliably, and so special switches have been designed such as puff switches and muscle movement switches. Additionall equipment is used with switches to hold them down and secure them in place - we usually refer to these items as "mounts". It is important to secure the switches so that they don't get pushed or fall.

  • Adapted keyboards: Expanded keyboards have larger, more widely spaced keys. Some keyboards are colour coded. Keyguards and protectors as well as grids are available. One can use a qwerty keyboard, but for some people, the qwerty is not great so adaptations are available.

  • Adapted computer mouse: Various options are available such as a trackerball which may be helpful if the person cannot grasp a mouse or move it over the surface of a table.

  • Pointers: Lightpointers and infra-red pointing devices can be used with some communication aids and computers. These are worn on the head - or sometimes on another reliable part of the body such as a shoulder -  and transmit a beam of light to the equipment being controlled. The computer or communication aid responds to the light beam as if the keyboard has been touched. Pointers can be low tech too.

AAC for language learning

Many children who are unable to speak because of speech and/or language impairments have difficulty  learning language. In addition, many children who are able to speak have language-learning difficulties. We use AAC to help children to learn language.

Learning language as a child who has difficulty speaking can be a real problem - typically developing children babble and play with words; they learn to use inflections to ask questions and make statements; they learn to talk their way through things and get themselves in and out of situations using words; they play with words; they make jokes.

Children who have speech and/or language impairments often do not learn these aspects of speech and language  easily, if at all, because they do not get going on AAC early enough AND AAC is slow.

So, if you are wondering how to get started on AAC, here are a few tips:

1. Introduce AAC early. Get going as soon as possible!

2. Give the child the opportunity to 'AAC babble' - press the buttons, choose the symbols, make random choices, even if it is all just babble - it is through babble and play that early learners learn!

3. Model, model, model. The adult needs to model the AAC. Everything you want to say to the child, say on the device! Regular day to day modelling has been shown to be the most effective way to get a child to use AAC successfully. We call this approach "aided language modeling" or 'aided language input". Whether one is using a high tech device or a low tech communication device such as a communication book, the communicative partner who wants to teach the person to use AAC models the AAC for the communicator, using as many symbols as possible.  See this link:

4.  Do not limit the child's vocabulary choice. It is virtually impossible to communicate if one has only a few words to choose from and we cannot LEARN language - such as grammar - if we don't have the words to choose.  Always give more than you think the child needs. There are wonderful pre-prepared AAC software programmes designed by speech therapists who know what the CORE words are that children need to both communicate and learn language. Don't re-invent the wheel. Do not assume that the words need to be developmental; they do not need to match what you think is the person's intellectual level; they do not need to be restricted to the words you assume the individual needs.

5. Don't introduce  AAC competing systems unless the child can cope.

6.  The AAC system must be available in every single context of the child's life - the bath, at school, in the bus, while in bed. So, you may need to use the dedicated high tech device, AND  a poster stuck on a wall, AND a communication book, AND an eye gaze mat or frame.... it is no good NOT being able to communicate in some contexts!!!!

7. Use the device for a wide range of communication functions- arguments, shouting, negotiating, joking, teasing, requesting, telling, and so on. Using AAC for real, deep communication in all contexts - in other words, as a full communicative partner -  is one of the challenges for all AAC users, so start early.


The contemporary approach taken by many speech therapists when working with individuals who use AAC is to presume competence.  Assuming that a person is incapable of using AAC or that he or she is not able to use AAC more competently is a very dangerous assumption. The "least dangerous assumption" is to assume that the person CAN. In this way, the individual is given the opportunity to learn and grow and change. For example, If a child has no language whatsoever, we do not say that the child cannot use AAC. Rather, we take the approach that we assume that the child will learn language by using AAC.It might not happen, but if we do not give the child the benefit of the doubt, we will never know.

But we have to be reasonable and sensible too. Presuming competence does NOT mean that we set unrealistic expectations. Presuming competence does not mean that we mislead people into believing that AAC will be effective and efficient and successful for all.  


In South Africa, there is no formal professional specialization in AAC. All speech therapists receive training at an undergraduate level to assess and provide individuals with AAC. Just as with any other area of interest, one can elect to do a higher degree with a focus on AAC as the topic. Having a higher degree does NOT qualify one as a specialist, and there is no registration with the HPCSA as a specialist. No speech therapist may "sell" themselves as having a special interest in AAC or as an "AAC practitioner". AAC is also not only a field of study restricted to speech therapists. Teachers, occupational therapists, physiotherapists and others may elect to study and practice in AAC but with a profession-specific focus. 

Useful Links









EDIT Microsystems


ISAAC (International Society for AAC)

bottom of page