The ordinary language we use in everyday life is good enough for everyday purposes, but when you use ordinary language to think about extraordinary problems that they were not originally designed for, then language can suggest ways of thought that are systematically misleading. For example, we all know what it means when someone says "The average American family has 1.4 cars". But suppose someone is misled by its similarity to the sentence "The Jones family has 2 cars", and starts wondering about where to find this average American family, where he can find their phone number and so on. This is an artificial example, but meant to show how language can trip you up if you are not very careful.
Gilbert Ryle wrote a paper on this theme: "Systematically Misleading Expressions". But Ryle's thesis was inspired mostly by Wittgenstein, who once wrote: "Philosophy unties the knots in our thinking, hence its result must be simple, but its activity must be as complicated as the knots it unties."