We have "nonchalant" but we don't seem to have chalant. What does the "non-" prefix refer to if there is nothing for it to not be?

Here in Pittsburgh we have amongst a lot of other stupid words, "yins" or "yuns" (The latter being pronounced as a short oo sound like book) . Thet are both plural versions of "you". A friend of mine has speculated that it may be due to the Irish population that emigrated here, and believes it may come from the Irish "sibh" (you, plural). I think he's reaching a bit, but we've been using that in Irish class. For example, when asked what "agaibh" means we answer "at yins" This is the only time I use it. It didn't take more than one or two trips away from here to realize that our lingo sounds pretty stupid.

Rich