Users of such devices instruct the device to select and speak any of the pre-stored messages by entering a sequence of keys represented with specifically chosen symbols. Each message is represented by a unique sequence of symbols and or letter codes. Many hundreds of messages can be stored using a relatively small set of multimeaning symbols which are chosen specifically for their broad semantic meaning.
Sequences are typically between two to four symbols in length.
During the past four years therapists in CCA have produced customised symbol sequenced vocabulary to suit the specific needs of South Australian users. There was great success in using key linking or symbol sequencing with a broad range of clients within various settings to enable clients to have access to wider vocabulary than by simply using single message systems or the use of multiple vocabulary displays as in a levels based system. As a result of the success clients were having with using symbol sequencing type systems it became necessary to investigate options for quick and easy methods for recording the vocabulary and organising individual dictionaries and support materials. In addition to finding a suitable system to record customised vocabulary in a dictionary format there was also a very significant need for a system which enabled the generation of specific therapy and teaching materials to support clients learning to use devices with key linking or symbol sequencing. Teachers, therapists and therapy assistants were spending inordinate amounts of time creating worksheets, flashcards, word lists and custom dictionary listings.