Sometimes the differences among members of a morpheme consist in some special relation such as the assimilation of two phonemes which had been separated in one member but became contiguous in another member. E.g. one of the members of the Yokuts morpheme for ‘girl’ is 'goyo.lum'; before the plural morpheme, which consists of 'i' plus certain vowel changes (dropping the second vowel of the preceding morpheme, and changing the third vowel to /a/), another member of ‘girl’ occurs: 'goyyam' (after the vowel changes associated with the following 'i'). We say that the second member differs from the first by having /y/ instead of /l/, in a position where the /l/ would have been contiguous with the preceding /y/; the other change, the dropping of the second vowel, which brought the two /y/ as together in the second member, is described as being part of the 'i' ‘plural’ morpheme, and is thus part of the environment in which the second member occurs.
- Harris (1951), Pag. 210, n.25