This study presents a partial analysis of nouns ending in orthographic -sion, -tion (or -ion) and morphophonemic variations between these nouns and related stems. It deals with an area traditionally called derivation.
The frame of reference is that of Trager and Smith, Outline of English Structure, supplemented by subsequent revisions and additions to the general theory developed by the authors in their teaching. For the purposes of this study the morphemic analysis will be limited to “postmorphemes,” i.e., morphemes occurring at the end of the word. Everything which precedes the postmorpheme(s) will be called the “stem” and will not be further segmented. The “stem” may occur elsewhere as an independent word (mutation: mutate) or in composition with different postmorpheme(s) (ambition: ambitious). The following special symbols will be used: √ … “morphemes”; √ … “allomorphs”; √ …/ “morphophonemes”; ∽ “varies with.” In three cases (Y, T, S) a small capital letter is used as a morphophonemic symbol; these are denned below.