Language uses words to represent meanings so people can communicate their thoughts to each other. Words are often spoken or written, but they can take other forms such as symbols. People who do not speak may use symbols as a way to express their thoughts.
Symbols are used widely in everyday life as a kind of visual language. Road signs, care symbols on clothing, or direction symbols at an airport are examples of how symbols can convey information quickly and effectively. Symbols can be read, regardless of the person's language or literacy skills. People with communication difficulties may benefit from using symbols to understand what other people are saying, as well as to express what they want to say.
Symbols are mostly available as collections or sets. Several symbol sets are available which have been designed specifically for AAC. Most present the symbol together with the word or phrase (gloss) it stands for. Typically the word is printed above the symbol if the focus is on communication. Communication partners need to be able to see the words because they may not know what all the symbols mean. On the other hand, if the focus is on literacy, the reader may need to be able to see the symbols to help decode the written word. Beginning readers often point to words as they read, so the symbol is printed above the word.
The most frequently used in the UK are Picture Communication Symbols (PCS)™, Widgit Symbols™, Symbolstix™ and Blissymbols™: see the section on Graphic symbol sets for more details. There are also graphic symbol systems associated with specific high-tech communication aids, e.g. Minsymbols™ and Dynasyms™.
Choosing a symbol set for AAC communication
Symbol sets vary in important ways including: how pictorial, how guessable, how flexible, how consistent and how visually complex. It is important to choose symbols to match the needs of the individual. Selecting symbols for the communication environment is also important. Practical issues such as whether symbol software is available to produce materials, or which symbols are available for a particular AAC system, will also influence the choice.
- How pictorial Some symbol systems are more pictorial than others. However, abstract concepts such as 'through', 'tomorrow' or 'want' are difficult to convey in a pictorial way.
- How guessable When symbols are easier to guess, the person using them might find what they want by recognition rather than learning. Many guessable symbols represent objects, rather than abstract ideas, and may be represented in similar ways in different symbol sets. However, some symbol systems are not so easily guessable, and need to be learned.
- How flexible Sets of highly pictorial symbols are easy to guess, but may be less suitable for referring to all the uses of a word. Thus a symbol for 'water' might not work so well to express the message "my eyes began to water".
- How consistent Symbol systems where the symbols are built with consistent visual elements may be easier to learn. Consistent systems may also allow the user to express meanings which are not actually included in their AAC system, combining elements in different ways to convey new and subtle meanings.
- How visually complex People with visual impairments may find it easier to process symbols with particular features, e.g. black and white, line drawing, or high contrast colour.
- Selecting symbols for the communication environment Using symbols in everyday setting is recognised as a very effective element of Total Communication. If symbols are already in use around the school or centre that the person attends, ideally the same set will be used for the person's individual communication system.
- Choosing a symbol set to match the needs of the individual The symbols must support the range of words and types of word that they will need. This is particularly important for people with good language skills who may need numerous very specific vocabulary items, or abstract words, or symbols for grammatical elements.