...because most of our linguistic formalism is derived from written language, which is generally an artificial approximation of real language.

Remember grade school, with parts of speech, Conjunction Junction, and diagramming sentences? Well, think back to the last (non-trivial) sentence you actually said out loud. I challenge you to try to diagram that sentence.

Although there's quite a lot of research that's been done, surprisingly little of it deals with the way most of us really communicate.