ABSTRACT
There is a difference, however, in the manner in which the two systems become subjected to these changes. Contrary to the large number of phonetic changes which phonemes undergo independently of words (cf. p. 36), morphological changes bear only upon words, and not upon morphemes in general. This is not only because morphemes generally form integral parts of words, but primarily because the causes for morphological change lie not in mental categories but rather in the uses to which language puts them.
