17. The tangible computer-readable medium of claim 15 , wherein the attribute identified by the symbol is at least one of form, meaning and specific content of the utterance containing information.
17. The tangible computer-readable medium of claim 15 , wherein the attribute identified by the symbol is at least one of form, meaning and specific content of the utterance containing information. 18. The tangible computer-readable medium of claim 17 , wherein the form attribute identifies the physical form of the utterance containing information.