Considered as a modality, speech is very different from other modalities like written language or graphics.
|Serial||No parallel information.||Graphics|
|Temporal||Speech takes time and puts demands on the users memory.||Graphics|
|Volatile||Disappears as fast as it is presented.||Graphics|
|Open||No finite set of symbols.||Keyboard|
|Referential||Speech (language) can refer to non-visible objects.||Graphics|