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Points to consider for symbol systems

“The purpose of a communication display is to arrange language in space so individuals can ... say what they wish to say as quickly as possible, and can do so with a minimal amount of effort.”  (Blackstone, 1993).

“The selection of a functional and motivational vocabulary is critical for effective use of an augmentative communication device…..Vocabulary selection is an ongoing process”.  (DynaVox Systems Inc., 1999, ‘Selecting and Organising Vocabulary for AAC Users’).

Things to consider when using a graphic system
  • Does the graphic symbol system contain all the vocabulary necessary for now and for future needs?
  • What is the relationship of the graphic system to spoken English? Are key words only used or does the AAC speaker need to use a fuller range of grammatical words?
  • There may be problems with symbols for abstract words eg. like, want, is, if.
  • A graphic symbol system will be built up slowly, so the user can see and understand how to use the symbols they have access to through utterances being modeled by the communication partner.
  • No recall is needed because the graphic symbol system is present as a reminder all the time.
  • Words must always be present with symbols or pictures on a chat or in a book so any communication partner who can read can have a conversation with the AAC speaker. It is better to have the words above the symbols for communication, but under symbols for literacy.
  • As only one reliable movement is needed to access graphic symbol systems it is possible for people with very limited physical skills to ideally suited to those with severe physical impairments.
  • Does the AAC speaker have any vision or visual perceptual difficulties? This may affect your choice of graphic symbol system.
  • Symbol systems (e.g. Blissymbols) are much more powerful than pictures (Picture Communication Symbols or Widgit Literacy Symbols), but they may be initially harder to understand and learn.
  • Pictographic systems (e.g.Picture Communication Symbols, Widgit Literacy Symbols) require more vocabulary to allow the user to say what they want, whereas a symbolic language like Bliss allows the user to create new words without having to increase the size of their charts or books beyond a manageable size.
  • Graphic symbols systems don’t break or need batteries, but can get lost! So it is important to keep a backup (paper and on computer).
  • Communication books and/or charts need to be carried around with the AAC speaker.