Reveilled where did you get the phraseology of "rush hour"?
As for the evolution of spoken and written english, is it not the other way round?
As long as books and newspapers are printed in standard english then it wont change... much. To be honest i cant see spoken standard english changing much either (i have yet to hear a news broadcast or documentary performed entirely in vernacular)
What is worrying to me is when kids are completely unable to express themselves in formal written english but i suppose that so long as employers and examiners insist on a minimum level of english then it wont be a major problem... i hope.