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VOCAs (Voice Output Communication Aids) come in many shapes and sizes, with different synthesised voices, and may have the ability to record speech.

Different kinds of VOCAs

Some VOCAs use paper or plastic sheets with words or symbols to represent the words or messages that have been recorded. In this case, the set of words or symbols is 'static': it does not change. But other VOCAs display the words or symbols on a screen, like a computer – these 'dynamic' displays change according to what the AAC speaker selects: for example, selecting the symbol 'food' might change the display to a set of symbols for different things to eat.

  • Single message VOCAs speak a recorded message
  • Message Sequencer VOCAs allow the user to have a series of messages
  • Overlay VOCAs allow the user to select from a number of messages; overlays with pictures, symbols or words are placed are placed over the keys to show which one will say which message
  • Dynamic Screen VOCAs display symbols or graphics on the screen rather than on paper overlays

Selecting a VOCA

Contact a local or regional AAC Assessment Service to find out more about using a VOCA. The service would be able to show a range of equipment which can be tried as part of an assessment. Some centres are able to lend equipment, to try for a reasonable length of time, perhaps up to 3 months (there is usually a courier fee for this service). Suppliers of communication aid equipment will often lend equipment as well. See our Directory of AAC Assessment Services.

There are many considerations when looking for the most suitable VOCA for an AAC speaker:

  • Whether the AAC speaker will walk and hold the device, or whether it will be mounted on a wheelchair.
  • How the AAC speaker will operate the device: by touching the screen, using switches, an alternative mouse or by eye gaze or head movement. A local AAC assessment service will advise which means of access will best suit the AAC speaker.
  • Whether the AAC speaker will use spelling or symbols. If symbols, which ones are used already? Must the VOCA use the same symbols, or can a different but similar set be used?
  • What vocabulary will the AAC speaker need, both now and over the next 3 to 5 years. There are many different pre-programmed vocabularies available for computer-based VOCAs. More information about pre-programmed vocabularies.
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