Introduction -- What is language? What is it for words to have meaning? What is the meaning of words? These are the basic questions of the philosophy of language. And here's a natural-seeming way of answering them, Language is a system of signs which we use to communicate with each other. Communication is a matter of letting other people know what we think. The signs which make up language get theri meaning from our associating them with the thoughts we want to express. The meaning of words of common languages, such as English or French or Japanese, is a matter of a convention among speakers to use them with agreed associations.