" then we encounter “through,” “though,” “rough,” “cough,” and “bough”—five words that all end with “-ough” and not only don’t rhyme but don’t even have similar pronunciations. But “won” and “done” and “shun” rhyme? Are you telling me Dr. Seuss lied to me about English? "
― Kory Stamper , Word by Word: The Secret Life of Dictionaries