“The reasons for changes in the linguistic structure, on the other hand, cannot lie in tendencies of the speakers. Linguistic structure, after all, is defined as something independent of them. We assume that linguistic structure follows its own laws and that a change in linguistic structure is not due to tendencies of the speakers, but to dispositions in the system that undergoes change. A given linguistic structure may be thought of as being predisposed to move in certain directions and not in others. And here it is linguistic typology, with what it has to say about categories that seek out and favor each other and categories that shun or avoid each other, which must identify the causes of linguistic change.”