I am only going to introduce one contraction here but, sensing that it will probably lead to other examples, I have opted to use the more general heading. "Won't" is defined and used as a contraction, and it seems to be a contraction of "will not," except that this doesn't make any sense. We once had a perfectly sensible contraction that served the same purpose, but it has fallen out of use and is archaic. It would make more sense to use "shan't" instead, except that people will assume that you're quoting a line from Little House on the Prairie. Shan't is a contraction of "shall not" and is one that makes sense, whereas if we were to contract "will not," a better contraction would be "wi'nt," except that it sounds weird.