apply it to all forms of language use.
This is an ambitious task as it raises questions about the relationship between the different forms that rhetoric can take. This ambition reminds me of Whateley's extremely confident assertion that "...most of the rules of Speaking are of course applicable to Writing." In a similar manner, Burke's piece seems to be predicated on the idea that the rules of one rhetorical form can "of course" be applied to another. As discussed by @em_bley and @sophist_monster on the Whateley piece, there are obviously unique characteristics of each rhetoric form, the role of audience being one. The unique role of the audience in writing and speaking is also discussed at length by Douglass (also discussed by @em_bley) when he writes about how audiences reacted to him as a black rhetorician.