Reply to post:

Well, it does exist as a standard formal written form, but the spoken and informal forms do of course vary widely from town to town, let alone from sub-nation* to sub-nation.

^{*(I use this term at the risk of invoking the ire of residents of Wales, Scotland, and Northern Ireland. However, be assured that I also include England as one of the sub-nations, so please don't freak out. We're a nation of sub-nations.)}