What enhances the humor of "The Celebrated Jumping Frog of Calaveras County"?
The humor of the story is enhanced by the contrast between the narrator and Simon Wheeler, the descriptions of Jim Smiley's betting and the satire of human foibles that Twain is able to communicate. The first bit of humor comes in the form of the obvious distaste the narrator, an Easterner, has for the uneducated Westerner, Simon Wheeler. The narrator says that Wheeler backed him into a corner and "reeled off the monotonous narrative which follows this paragraph." But the narrative is hardly monotonous. It is full of wonderful descriptions of a con artist who gets conned. The narrator's description of Simley's obsession with gambling is full of funny details, like when he would he would" foller that straddle-bug to Mexico but what he would find out where he was bound for and how long he was on the road." Wheeler even bets on the death of the minister's wife. When the ministers says his wife is getting better, Smily thoughlessly says, “Well, I'll risk two-and-a-half that she don't, anyway.”
In addition, the descriptions of the "15 minute nag" and the bull dog who died of embarrassment are as funny as they are unbelievable. When training his frog to jump, the Smiley is especially funny. But the real entertainment value is the irony at the end of the story when Smiley is outfoxed by a stranger who puts quail shot in his frog. Finally, the narrator has had it with Wheeler's story and says so, but the reader has certainly had a good laugh.
The very notion that there would be a young reverend in a mining camp is humorous because mining camps were notorious for all manner of immoral behavior and the absence of virtuous women and men of the clergy. The invented name of the absent reverend, "Smiley," is meant to emphasize the humor that the narrator has been sent on a fool's errand.
The Western dialect that Simon Wheeler uses is also meant to enhance the story's humor. Nonstandard words and phrases like "straddle bug," "foller' (for "follow"), "bannanner," (for banana), "bully-rag," and "sorter discouraged-like" would be funny, especially to a more educated, or perhaps Eastern, audience unused to such colorful language.
Smiley's description of the posture of the frog as it attempts to jump (it "hysted up his shoulders so like a Frenchman") is a humorous and harmless swipe at Europeans that would likely amuse the nineteenth-century audience.
The exaggeration of some elements of Wheeler's story also create humor. At the story's end, his claim that the frog "belched out a double handful of shot" is impossible and utterly ridiculous.