I picked this up months ago for a uni module, the first block of which involved analysing translations of Harry Potter in different languages. Hands down the most excited I've been about secondary reading, needless to say. I'd kind of come across the topic before thanks to the internet, so I'd already had a laugh that Harry waves a "baguette" in the French translation, or that to form the anagram "Je suis Voldemort" Tom's middle name became Elvis (which I very much hope is not a spoiler at this stage), but really getting into it, I found the topic endlessly interesting, not to mention it gave me a greater appreciation for the original series, as well as for the struggles of translators.
Example: the Italian translators took the "Dumb" in Dumbledore- in the sense of lacking the power of speech- and rolled with it to create Professor Silente. However, Rowling later said in the interview she'd had an Old English word for a "humming insect" in mind, the headmaster in her mind wandering around the castle humming to himself, not silent at all. Rather than being a poor translation though, Dumbledore does keep things from Harry for the greater good in the series, leaving the surname Silente somewhat prophetic.
I may be in the minority here admittedly, but I recommend checking out his book, or books/articles like it, if you're a Harry Potter fan with even the teeniest interest in languages. Although actually the Spanish translations from what I remember seemed awfully literal which takes a lot of the fun out of it. Anyway, I leave you with two bits Fred&George hilarity for the price of one:
"How do you feel, George?"
"Saint-like," he murmured..."You see...I'm holy. Holey, Fred, geddit?"
"Come ti senti, Georgie?"
"Romano" mormorò..."Sai...mi sento un po' romano. Come il foro. Il foro, Fred, capito?"
-which could be translated:
"How do you feel, George?"
"Roman" he murmured..."You see...I feel a bit Roman. As in the Forum. The hole, Fred, geddit?"
What a pun-save.