Twain uses the dialect of rural California to fully characterize Wheeler with local color.
Wheeler uses descriptive language to describe things in a way that uses local color, or dialect representing a region. Since the frog jumping contests takes place in a rural area of the California hills, Wheeler represents a rural mindset. To Wheeler, the contest is an “important manner.”
Wheeler is described as a “good-natured, garrulous” country man. He is a simple man, “fat and bald-headed, and had an expression of winning gentleness and simplicity upon his tranquil countenance.” He “never smiled, he never frowned, he never changed his voice from the gentle-flowing key” in which he started. (p. 1)
Wheeler uses idiomatic expressions, or cultural figurative expressions. For example, when he picks up the frog he uses an idiom.
"Why, blame my cats, if he don't weigh five pound!" (p. 4)
The phrase “blame my cats” is figurative. He is not actually blaming any cats for the weight of the frog. Another example is “he was always ready and laying for a chance” (p. 1) meaning waiting and not literally laying, and “he would foller that straddle-bug to Mexico” (p. 2).
Wheeler uses unusual adjectives and adverbs, such as “curiosest,” “uncommon lucky,” and “anywhere” (p. 1-2).
Wheeler uses dialect by pronouncing words differently than we would, and Twain writes them as they sound. Examples of this are “solittry,” for solitary, “reg'lar” for regular, and “feller'd” for feller would (p. 1-2).
Wheeler uses hyperbole, an exaggeration that is a type of figurative language, when he says of Smiley, "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." In other words, Wheeler says that Smiley would follow a straddle-bug all the way to Mexico to see if he (Wheeler) had won the bet about how long the bug would take to get somewhere; this is obviously an exaggeration.
Later, Wheeler says of Smiley's pup, Andrew Jackson, "But as soon as money was up on him, he was a different dog; his underjaw'd begin to stick out like the fo'castle of a steamboat, and his teeth would uncover, and shine savage like the furnaces." Wheeler uses a simile to compare the dog's jaw to the forecastle (or upper deck) of a steamboat, and he also uses a simile to compare the dog's shining teeth to blazing furnaces.
When Wheeler is describing the jumping frog, he says, "the next minute you'd see that frog whirling in the air like a doughnut." He uses a simile to compare the frog's midair acrobatics to the way a doughnut would whirl in the air if it were thrown. Wheeler later says of the frog, "he was planted as solid as an anvil." In this simile, Wheeler compares the frog, who can't move, to an anvil, a very solid object on which other objects are struck.