Howdy Torog! Naturally, some of the biggest differences between northerners and southerners are language-related, but I was surprized by the general confusion I got when I referred to an apartment as a 'flat.' As I understand it, (at least up north) the term flat applies to a "house style apartment" as opposed to the standard apartment-complex-type apartment. When I tell folks I have an apartment down here, they want to know how I'm enjoying the fitness room and swimming pool. To which I can say, "well... there's an oak tree in the yard... and I enjoy that just fine."
mike

ps- we also refer to "drinking fountains" as "bubblers." I have no idea why.