Try talking to a
Glaswegian :-)(that is actually the first time I've written that word - I very much doubt there's a node at the other end of the link. especially as I've probably misspelt (misspelled?) it).
The point about English, and indeed language in general (IMHO - some officious French people are of the opposite opinion) is that it evolves. Like genetic variation in a crop, this only serves to strengthen a language - and, by extension, the ideas of those who speak it. I'm not implying a cultural superiority here; I'm sure many languages are flexible, despite attempts to simplify or standardise. Rule mongers (gaming term:) who insist on the intact virtue of infinitives are missing the point.
So long as a language remains understandable, change (even rapid or transient change, like slang) is useful and natural. If American English is guilty of anything it is simplification for its own sake, especially in spelling. However, I rarely criticize anymore after reading Mother Tongue, which made me a modicum more humble.