Glossary of Terms


Access : Body parts

A range of body parts may be purposefully designed for a access solution. For example a head or hand or a foot. 

Access : Input Required

Access solutions require a way of controlling the device. This can be varied - it could a very light, small (discrete) movement or a larger gross movement (e.g. with a hand). This type of action may be due to the amount of pressure required. Some solutions (e.g. mice, eye gaze ) require a co-ordinated movement to control the solution in a range of directions. Lastly, some solutions may be require a specific type of action from a muscle - this may lead to extremely small movements being required to activate the solution. 

Access : Output

Access solutions may have numerous ways of outputting from the input (e.g. pressure or co-ordinated movement) required. This maybe a single press of a key (like a switch) or allow several single binary outputs. Some solutions (e.g. a mouse) allow for a range of control across a system. 

Access Method
Refers to the method by which an individual accesses their communication system.
Access type

Access solutions are defined as Switches, Eye Gaze systems, Mice, Keyboards or Brain Computer interfaces. 

Alphabet chart

An alphabet chart is a form of low tech AAC.  The alphabet is displayed so that an individual can select letters to support their face-to-face communication.  

Associated Costs

Some products need additional licences or peripherals to function for a particular users needs. 

Auditory scanning

An access method that is a form of listener mediated scanning.  The options are read aloud and the individual indicates when they have heard the target option.  On a high tech system, the individual may activate a switch when they hear the target option.

Augmentative and Alternative Communication (AAC)

The term used to describe various methods of communication that can be used as an alternative to or an ‘add-on’ to speech and are used to get around problems people may have with ordinary speech. AAC includes simple systems such as pictures,gestures and pointing, as well as more complex techniques involving powerful computer technology.


Refers to the saving of an individuals data on a memory stick or sometimes to "the cloud". This means changes to communication pages can be saved and swapped between devices in event of technical issues.
Battery Life
Refers to the length of time a battery is expected to last on continuous use before the device will need to be charged again.


Capacitive Touchscreen

This is a type of touchscreen.  A capacitive touchscreen is activated by the electrodes in the screen recognising the conductive properties of an object touching it, rather than by pressure.  This means that it can be activated by a very light touch, but also that it will not react at all to being touched by certain objects. In contrast, a resistive touchscreen requires slightly more pressure to activate it, but it will respond to being touched by any object.


A term used to describe a defined shape on a screen or page that contains a symbol and / or label.  It is often square or rectangular in shape with a defined border.

Coded Access

An access method that tends to be associated with low tech AAC.  Symbols or letters are effectively given a grid reference that the individual then communicates.  It requires two separate charts to communicate.  One chart displays your symbols or letters, the other is used to communicate the location of the symbol or letter you wish to communicate. 

Combination Access

An access method that is usually associated with low tech AAC.  It involves using a combination of two or more access methods to access a communication system.  For example, pointing plus listener mediated scanning.  

Communication Partner
A communication partner is anyone that a person using AAC communicates with.
Communication Passport

A communication passport is a document that provides information about how a person communicates.  It can be in printed or electronic form, and may be text and / or video based.

Core Vocabulary

Words that are useful across lots of topics of conversation and are frequently used.  For example, ‘more’, ‘stop’, ‘help’.  Core vocabulary is identified in empirical research or clinical reports that measure vocabulary use patterns across many individuals.  Often used in contrast to the term fringe vocabulary which refers to words that are specific to an individual, or to a certain topic of conversation or situation.


Dedicated Device

A communication aid that is built for the purpose of communication. A dedicated device might also have other functions such as use of the internet but is originally designed to be used as a communication aid. An iPad for example is not a dedicated device.

Some devices are mainstream products and can be made dedicated by locking the software into the device. Only with specialist skills, knowledge could the device be unlocked. 

Digitised Speech
Some AAC devices use digitised speech as their voice output. Digitised speech is recorded speech usually recorded by a communication partner on the device itself via a built in microphone.


E - Tran Frame
A low tech communication system usually comprising of a clear perspex frame to which symbols or letters are added. The frame is held up in front of the individual who then eyepoints to the appropriate letter or symbol to communicate a message.

Encoding describes the grouping of letters or symbols together to facilitate access.  Selection involves two steps - the individual must indicate the group that contains their target letter or symbol and then identify the precise letter or symbol. It is often associated with eye-pointing, but can also be used to facilitate direct access.  It tends to be found in low tech communication systems.

Environmental Control

A form of electronic assistive technology which enables people with physical disabilities to independently access equipment in their environment e.g. home or hospital. It is at times shortened to EC.


A low tech communication chart where letters are printed or placed on a transparent material.  This is held up between an individual and their communication partner, and the individual looks directly at the letter they wish to communicate.  The communication partner moves the chart until they are looking at the same letter, and speaks aloud the letter to confirm the selection.


Eyegaze systems can allow people with severe physical disabilities to access a communication aid or computer using their eyes. These devices have an inbuilt camera which tracks where you are looking and allows an individual to select something by blinking, dwelling (staring) or clicking a switch.


Form of Representation

How is language represented? Symbols, Photos, Objects of reference, Videos, Letters/Words etc.

Fringe Vocabulary
Vocabulary specific or unique to the AAC user or to one activity or topic. (Beukelman & Mirenda, 1998)


Guide Price

This refers to the base price suggested by the reseller. Not to include Tax e.g. VAT/GST if possible.


Hardware Advanced
This terms refers to high tech AAC systems which are computer based systems usually with a dynamic display that allows the storage and retrieval of multiple messages and multiple levels of message usually as part of a vocabulary package.
Hardware Simple
This term refers to light tech AAC solutions or AAC devices that require a battery. They usually support a small number of messages and use synthesised speech.


A mobile operating system developed by Apple Inc.


Listener Mediated Scanning

This is an access method whereby the communication partner delivers the options available to an individual.  The individual then indicates when they have seen and / or heard the desired option, thereby communicating a message.  The options may be delivered by speech alone (auditory scanning), by simply pointing the options available (visual scanning) or by speaking aloud the options whilst pointing to them (visual and auditory scanning).  Also known as partner assisted scanning.

Low Tech Communication
Refers to a communication system that does not require a battery, this includes a paper alphabet board, symbol board, E Tran frame or pen and paper.


Message Levels
Refers to the number of 'levels' a communication system can store vocabulary. This usually refers to Hardware simple or 'light tech' solutions.

The communication partner points to symbols on the communication system whilst talking to the person who uses AAC.  The communication partner is demonstrating how to use the communication system in context.  Also known as point-talking or aided language stimulation.  

This is a piece of equipment (separate to the communication device) that is used to position a device in a certain place. Different types exist such as a table mount, wheelchair mount or floor mount for example. These are used to find an ideal angle and distance to optimise the use of the device for the users needs. 'Mounting' is a term used to refer to the set up of a mount (this may require professional support to ensure the equipment is positioned safely, especially when mounting a device to a wheelchair).
Mouse Alternative
There are several alternative forms computer 'mice' that allow other ways of moving a pointer around a screen, selecting, clicking and double clicking when a typical computer mouse is difficult to use.


The process of moving through pages or rows of vocabulary on an AAC device.


Objects of Reference

A form of low tech AAC.  Objects of reference are objects or things that are used to represent concepts e.g. a plastic cup might be used to represent the concept of having a drink.  Objects of reference may be used to help someone remember something, to help them understand something, or to help them anticipate something that is going to happen.   An object of reference may also be used by an individual to express themselves.

Operating System (OS)
Software that manages computer hardware and software resources and provides common services for computer programs.



PECS®️or Picture Exchange Communication System®️ is a scheme which teaches people on the autistic spectrum the purpose of communication by requiring them to physically exchange a symbol with a communication partner.

Partner Assisted Scanning

This is an access method whereby the communication partner delivers the options available to an individual.  The individual then indicates when they have seen and / or heard the desired option, thereby communicating a message.  The options may be delivered by speech alone (auditory scanning), by simply pointing the options available (visual scanning) or by speaking aloud the options whilst pointing to them (visual and auditory scanning).  Also known as listener mediated scanning.


Recorded Speech

See digitised speech.

Resistive Touchscreen

This is a type of touchscreen.  It is activated by pressure.  Activating a resistive touchscreen tends to require slightly more pressure than a capacitive touchscreen.  However, unlike a capacitive touchscreen, it will respond to being touched by any object.


Software to control of computer

Some software can be enabled to pretend to be a regular mouse/keyboard so that a user can use their regular communication system to control a computer. This may be a different computer or the same as one that the device is currently running on. 

Speech Type

Speech may be recorded or synthesised. 

Symbol Set

A group of pictorial symbols with a common design theme. There are a number of different symbol sets that are commonly used on communication aids. Symbols (in AAC terms) are pictorial representations of language and may or may not be combined with written words or phrases.


Special pictures that are used to represent concepts e.g. a drawing of a person drinking out of a cup might be used to represent the concept of having a drink.  They are used both to support understanding and to help someone express themselves.  A group of such pictorial representations of language is known as a symbol set.  

Synthesised speech
The artificial production of human speech by a computer or communication aid. This is usually done via text to speech (TTS) software and a variety of voices are available from a number of suppliers.



Stands for Text to Speech.  A synthesised voice speaks the text that is entered into the communication system.

Tangible Symbols

Tangible symbols are symbols that can be felt with the hands or body.  Sometimes used as another word for objects of reference.  Also used to describe more abstract symbols created using different shapes and textures.  In the latter context, also known as tactile symbols.  

Text to Speech

Also known as TTS.  A synthesised voice speaks the text that is entered into the communication system.


Videos - Vocabulary

We would like to capture a range of communicative functions in the videos. So consider for example how you would request, initiate, comment, greet, provide information using the software/vocabulary and video examples of that. 

Visual Scene Display

This refers to a way of presenting information on a screen or page using a photograph or illustration of a scene.  Instead of a chart containing vocabulary of items in a living room for example, there might be a photograph of the living room.  On selecting the television in the photograph, for example, you might then access vocabulary to talk about the television.  

Vocabulary Package
A ready made series of communication pages grouped together in a specific format or structure that follow a language pattern or philosophy. These are popular templates or starter pages that usually require a degree of editing to reflect an individuals personality, interests and communication style.