Stump speech (minstrelsy)

The stump speech was a comic monologue from blackface minstrelsy (which is an American entertainment consisting of comic skits, variety acts, dancing, and music, performed by white people in blackface). A typical stump speech consisted of malapropisms (the substitution of a word for a word with a similar sound), nonsense sentences, and puns delivered in a parodied version of Black Vernacular English. The stump speaker wore blackface makeup and moved about like a clown. Topics varied from pure nonsense to parodies of politics, science, and social issues. Although both the topic itself and the black character's inability to comprehend it served as sources of comedy, minstrels used such speeches to deliver social commentary that might be considered taboo in another setting. The stump speech was an important precursor to modern stand-up comedy.

The stump speech was usually the highlight of the olio, the minstrel show's second act. The stump speaker, typically one of the buffoonish endmen known as Tambo and Bones, mounted some sort of platform and delivered the oration in an exaggerated parody of Black Vernacular English that hearkened to the Yankee and frontiersman stage dialects from the theatre of the period. The speech consisted of a barrage of malapropisms, non sequiturs, puns, and nonsense. The stump speaker gestured wildly, contorted his body, and usually fell off his stump at some point. Speakers often took on the persona of popular minstrel show characters, such as the black dandy Zip Coon.

...
Wikipedia