My edition was edited by Henry Nash Smith, whose Introduction is worth reading. In his insightful curating, he makes this fascinating point about Victorian language:
Just as effective as the individualizing of the characters by their speech is Mark Twain's device of establishing a common diction and rhetoric for all characters the moment they try to claim for themselves a false pathos...or an undeserved moral authority.... Different as the characters are in their natural selves, when they fall into pretense they all sound alike because they all begin to speak in a burlesque of the exalted rhetoric of the official culture. This "high" language might be called the "alas!" or the "soul-butter" mode of speech.(The term "soul-butter" is Huck's own invention, which he uses after watching a transparently phony speech by the Dauphin, and the watching crowd strikes up "the doxolojer": "Music is a good thing; and after all that soul-butter and hogwash, I never see it freshen up things so, and sound so honest and bully.")
We don't do "soul-butter" much anymore -- and probably rightly so. If asked to deliver, say, a eulogy, I would shoot for tasteful, direct language rather than hifalutin phony poetry -- for precisely the reason Smith points out: We're trained (not least of all by Mark Twain himself) to view that "Alas!" school of rhetoric as a disguise for pretense and dissembling. The writers of Deadwood understood this brilliantly; the chief source of soul-butter in that cast of characters was the loathsome, sticky E. B. Farnum, who never spoke any other way.
Of course, there's good soul-butter and bad. The Gettysburg Address, I think we'd all agree, is very good soul-butter indeed, an application of "exalted rhetoric of the official culture" put to good use. King's "I Have a Dream" speech. Twain's hysterically funny poem, attributed to the young, departed Emmeline Grangerford, "Ode to Stephen Dowlding Bots, Dec'd," ("Then list with tearful eye/Whilst I his fate do tell/His soul did from this cold world fly/By falling down a well") would occupy the opposite extreme. The poem on the obverse of John Mobberly's gravestone? Quite awful Victorian soul-butter.
Here's one of the reasons why Huck Finn is relevant to the Origins of Bluegrass: Quite a few of the sentimental Tin Pan Alley songs that formed much of the early repertiore were lyrically quite soul-butter-intensive: Think of "The Little Girl and the Dreadful Snake":
I heard the screams of our little girl far awayMmm, pour that melted soul-butter over my popcorn, an' throw in some salt! I'm here for the duration!
Hurry daddy there's an awful dreadful snake
I ran as fast as I could though the dark and dreary woods
But I reached our darling girl too late
Oh, I began to sigh, I knew that soon she'd have to die
For the snake was warning me close by
I held her close to my face she said Daddy kill that snake
It's getting dark, tell Mommy goodbye