In many cases there is no phonemic similarity between the various members of a morpheme and the environments in which each member occurs: in 'good-better' /bet/, which occurs before 'er', is no similar to /Ər/ than is /gud/. Sometimes, however, we find similarities between a member and the environments in which it occurs: we may say that the phonemic form of the member depends upon the phonemic form of some part of the environment. This is more frequent when the environments of a member are identifiable by a common phonemic characteristic […].The [phonemic] similaritiy may consist in some features of a phoneme, i.e. in some components. Of the morphemic segments /s/ and z/ which are included in {s} ‘plural’, and of the segments /t/ and /d/ which are included in {'ed'} ‘past’, we find the voiceless member occurring after morphemes ending in voiceless phonemes, and the voiced member after voiced phonemes: /buks/ 'books', /wayns/ 'wines', /bukt/ 'booked', /waynd/ 'wined'. Even the memebrs /Əz/ and /Əd/ which are included in these two morphemes have a relation, though a dissimilation one, with their environments. These occur only after voiced or voiceless consonants homo-organic with their own: /'gæzƏz/ 'gases', /'glæsƏz/ 'glasses', /'ædƏd/ 'added', /'mƏlktƏd/ 'mulcted' […]. The [phonemic] similarity may also consist in identity of a whole phoneme […]. In the Attic Greek reduplication, the consonant of each member is identical with the initial consonant of the environment-constituting morpheme which follows it. In the Yokuts reduplication, all the phonemes of each member are identical (in the same order) with the phonemes of the preceding morpheme which constitutes the environment determining the occurrence of the particular member.
- Harris (1951), a pag.212