"Why is it that languages always change? It's easy enough to see why we need to have common agreements on grammar and vocabulary in order to be able to talk to one other. But if that's all that we need language for, one would think that, once a given set of speakers found a grammar and vocabulary that suited their purposes, they'd simply stick with it, perhaps changing the vocabulary around if there was some new thing to talk about--a new trend or invention, an imported vegetable--but otherwise, leaving well enough alone. In fact, this never happens. We don't know of a single recorded example of a language that, over the course of, say, a century, did not change both in sound and structure. This is true even of the languages of the most "traditional" societies; it happens even where elaborate institutional structures have been created--like grammar schools, or the Academie Francaise--to ensure that it does not. No doubt some of this is the result of sheer rebelliousness (young people trying to set themselves off from elders, for example) but it's hard to escape the conclusion that ultimately, what we are really confronting here is the play principle in its purest form. Human beings, whether they speak Arapesh, Hopi, or Norwegian, just find it boring to say things the same way all the time. They're always going to play around at least a little. And this playing around will always have cumulative effects. (p. 200)"