Process adequately covers the variety of formal associative relations found between root and stem forms [...] and members of the paradigms, and provides a single means of describing the formation of these words by reference to a constant or common element [...] underlying them, whether or not the root or stem form itself serves as a paradigm member or not. The processes involved in languages include affixation [...], alternation of vowel and/or consonant structure [...], reduplication in whole or part of base form [...], stress difference [...] and tone difference.
- Robins (2004), Pag. 148