Parker’s post on genres is great. It nicely captures the fact that, when aspects of rhetorical context like speech act (or purpose) are repeated often, they give rise to genres. One common workplace genre is the directive. You may notice that these speech acts fall within the four purposes identified in my tutorial: representatives = informing, directives = directing, questions = consulting, and commissives + expressives = valuing. Declaratives, however, are something “special.”
And then there’s one of my favorite genres, the proposal. Going by the speech acts outlined, it’s is a hybrid of representative (identifying a state of affairs–a problem or opportunity), directive (trying to persuade a reader/gatekeeper to accept/believe in your solution), and commissive (outlining commitments in regard to time and $$$).
I think this is it exactly! I would argue that the primary or ULTIMATE purpose in a proposal is directive (directing the reader to accept what’s proposed) and that the representative (informing) and commissive (valuing) purposes are subordinate. To me, the whole document fails if the reader doesn’t accept it.