than even they can imagine. When Sam climbs a nearby mountain to judge the reaction to their dastardly deed, he is surprised to see nothing more than "a sylvan attitude of somnolent sleepiness pervading that section of the external outward surface of Alabama that lay exposed to (his) view." The men's underestimation of the area's characteristics is further emphasized when the response to their ransom demand comes, not as a result of the comparatively sophisticated "counterplots" that they expect, but at the hands of "a half-grown boy (who) rides up the road on a bicycle," leaves behind a single sheet of paper, and pedals away.

The final insult resulting as a consequence of the two would-be criminals' misjudgement of the character of the area occurs when the father of the boy they kidnapped nonchalantly suggests that instead of him paying the money demanded, they should pay him, the father, to take the boy off their hands. Rather than being frantic for the safety of his child, he is calculatingly practical in his response, unsentimentally understanding the nature of his son. After all that has transpired, Sam and Bill are only too happy to fork over two-hundred and fifty dollars so that the father will take back the horrid little rascal!

     Regionalism refers to the use of local color and is a major contributor to the enjoyment of O. Henry's, "The Ransom of Red Chief."  The author introduces the setting as a small semi rural town located in Alabama.  O.  Henry also refers to a publication known as, Weekly Farmer's Budget, when he describes the small town police force.  O. Henry writes, "We knew that Summit couldn't get after us with anything stronger than constables, and, maybe some lackadaisical bloodhounds and a diatribe (criticism) or two in the Weekly Farmer's Budget."   This statement gives the reader the stereotypical image of a southern small town sherriff and his trusty bloodhound.  The kidnappers use eloquent southern speech full of similies and the occasional Biblical allusion.  O. Henry states, "Just then we heard a war whoop, such as David might have emitted when he knocked out Goliath."  Southern speech often uses characters from the Bible as a basis for comparison.  Combine that with yawp, whoop, and ain't, and the reader senses the local color of southern speech.  A final note is the food described during their supper. They are eating bacon, bread, and gravy, all staples of southern cooking. The word gravy is used to describe a sauce when referring to southern style cuisine. The author's use of local color creates a sense of realism within the story.  The reader can hear the soft southern accents, visualize the small rural town, and smell the food cooking at the campsite.

Reference

"The Ransom of Red Chief, " by O.  Henry taken from:

Allen, J, Applebee, A, Burke, J, Carnine, D, Jackson, Y, Jago, C, Jimenez,R, Langar, J, Marzano, J, McCXloskey, M, Ogle, D, Olson, C, Stack, L, Tomlinson, C. (2012). Literature. Holt McDougal, Houghton Mifflin Harcourt, Orlando. 50-61.

When you say "regionalism," I assume you mean words or allusions or things like that which would be specific to a particular region.  This particular story is set in Alabama, but I would argue that the author uses a more general type of regionalism -- I would say that he clearly sets out to make this a western/frontier rural American story.

Throughout the story, there are all sorts of references to Indians.  This starts with the boy being called Red Chief and goes on from there.  By having so many of these kinds of references, the author places the story in the American frontier.

I think that the author does this as a way to say that the frontier is better than the city.  He has the two kidnappers be city men who think they can some easy money out of the country hicks.  They get outsmarted by a simply country boy, thus symbolizing the typically American idea that the frontier is superior to the city.

Regionalism refers to a style of writing in which the narrative of the story is written so as to "concentrate on the landscape, dialect, customs, and folklore specific to a geographic region or locale."

The irony starts quickly in "The Ransom of Red Chief." The landscape is described as being "as flat as a flannel-cake" but the town located on that plain is named "Summit." The story's narrator, Sam, endeavors to make himself sound sophisticated as he tells the story, but the dialect reflects Southern influence and the inadequate preparation for their plan that causes the failure of their plot.

Bill and me figured that Ebenezer would melt down for a ransom of two thousand dollars to a cent. But wait till I tell you.

What Bill and Sam don't know until it's too late is that the citizens of Summit all know "Red Chief" and are only too happy to be free of his mischievous behavior for awhile. Their lives can continue in the same pattern as always, only more peacefully than normal, while the boy is out of the scene.

There don't seem to be much excitement around Summit on account of his disappearance; but maybe they haven't realized yet that he's gone. His folks may think he's spending the night with Aunt Jane or one of the neighbours.

The dialogue of the story supports the atmosphere of the locale as well as the action and interaction between the characters.