How does a malapropism create humor by using a similar-sounding but incorrect word?

A malapropism creates humor by replacing an intended word with one that sounds similar but is contextually inappropriate, resulting in a "ludicrously wrong" or nonsensical statement. This verbal blunder functions as a figure of speech classified under the category of errors.12

The humor arises from the incongruity between the speaker's earnest attempt to sound sophisticated or precise and the unintended, often absurd, meaning produced by the incorrect word choice. For example, when a character uses "geometry" instead of "geography" or "reprehend" instead of "comprehend," the audience recognizes the speaker's failure to grasp the correct vocabulary, which highlights their pretension or confusion.123

This device is named after Mrs. Malaprop, a character in Richard Brinsley Sheridan’s play The Rivals, whose name itself is derived from the French malapropos, meaning "inappropriate". By using words that are phonetically similar but semantically mismatched, the speaker inadvertently reveals their own limitations, providing a source of amusement for the audience.32