Tangible Symbol Systems were designed for people who are unable to understand the meaning of the abstract symbols used in formal language systems.
Most people communicate through spoken and written words. Some people use alternative systems such as sign language, Braille or high-tech electronic devices. These systems all require an understanding of an abstract symbol system consisting of arbitrary sounds or characters.
Many people are unable to use these more familiar and abstract avenues of communication. Tangible Symbol Systems is a method of communication that uses concrete, rather than abstract symbols.