There's a whole cannon of literature written in it (Dunbar, Ferguson, Ramsay, MacDairmid, Henryson, Kelman, Leonard, Souter etc.) as well as a bit of a discussion whether the literature reflected or embellished Scots (Burns and MacDairmid both made up words for example). When people think of Scots they usually think of the Glaswegian dialect of English you commonly hear on the TV. But there's still a whole set of words in common use today around Scotland. You hear it more in rural areas and less in the central belt.