“Ever since Richard Brinsley Sheridan created the chronically misspeaking character of Mrs. Malaprop in his 18th-century romantic comedy The Rivals, we’ve had a convenient word with which to point out other people’s linguistic inferiority. But is saying “epitaphs” when you really mean “epithets,” as Mrs. Malaprop did, really a sign of ignorance? In fact, there’s much more to malapropisms than you might think. Listen as Bob Garfield and I [Mike Vuolo] discuss what a common speech error reveals about the way that our mental lexicon—that is, the dictionary in our head—is likely organized.”
Lexicon Valley podcast with discussion between Mike Vuolo and Bob Garfield using David Fay and Anne Cutler's 1977 article for scientific background.