...don't take this as an insult, but you got WAY to much time on your hands if you worry about that. Why do we say such things? Because someone said it and other people caught up on it till we did i guess. I don't know what language your first one is, but i am 100% sure that there are just as many word-cuttings or replacements in whatever tongue it may be. I know that there are plenty in mine for example. German has so many strange sayings and word-replacements, its beyond funny. Especially since we got a quadrillion of different accents as well, even tho few people from outside really know how many.