A process may have more than one representation. A single representation of a process is a marker. A marker consists of the difference between the phonemic shape of a derived form and the phonemic shape(s) of the underlying form or forms. That is, a marker may consist of phonemic material in some specific position relative to the phonemic material which is identical with that of the underlying form, or it may consist of something present in the derived form in place of something else present in the underlying form, etc.
- Hockett (2004b), Pag. 129