In English, "Prefect" and "Percy" both begin with "P." So how is Fred's tease treated in languages that don't use the word "prefect"? In some cases, Molly gets in on the joke.
Translating Harry Potter into Hebrew was an interesting choice. Only a century ago it was a holy language, but now it's used to translate tales of witches and wizards! The novelty of modern Hebrew is apparent in the translation, which reflects its young literary culture and its large number of non-native learners. See how it scores on the Spellman Spectrum!