Author J.K. Rowling confirmed the theory about Hermione pronouncing her name in the fourth book to prevent her readers from continuing to mispronounce it.
“It’s LeviOsa, not LeviosAR!” – Hermione Granger’s character is well known for correcting a pronunciation or two, such as one of her most iconic moments where she schooled Ron Weasley on the levitation spell. It was not only characters in the books that mispronounced spells or even names, but also fans and readers of the book series. Many readers were saying Hermione all sorts of ways before the fourth book Harry Potter and the Goblet of Fire was released and J.K. Rowling included a passage about the correct pronunciation. It looks like J.K. Rowling has a bit of Hermione in her, as the author just confirmed that she added it in to avoid any more confusion for readers.
A tweet from a fan brought up a long-time theory regarding a passage in the fourth book where Viktor Krum kept pronouncing her name as Her-my-own. The heroine corrected him and fans everywhere, by announcing it as Her-my-oh-nee slowly and clearly.
J.K. Rowling responded to the fan’s tweet, confirming that her intentions here were to school readers on how to say her name above anything else.
Theory correct. https://t.co/Q46h56ljuU
— J.K. Rowling (@jk_rowling) 18. September 2018