It's not indiscreet. I've never speak anything else other than french until I was eleven (Cursing in Macedonian, Serbian, Arabic and Portuguese does not count I guess. ^^) and perfectly is a bit too flattering but thx. ^^
Mostly my books are organized by languages, then genres and then alphabetically. Even if I have several times the same book in different languages I don't put them together.
There's exceptions like the dictionaries, grammar books, a few phrase books and some reference books on different litteratures. They have a shelf of their own rather close to my studying area. I often have to compare things between slavic languages and I can't afford to travel through my 5 rooms flat all day. This shelf is designed to allow the books I use the most to be the easiest to reach so to other's eyes it's a mess. ^^
One other exception is the big Artbooks and the valuable ancient books. They're displayed mostly in order to look nice in the living room.
And the last concerns my favourites. Almost on each bookshelf, I'll put a dozen of the stuffs I prefer forward regardless of any logical order. It doesn't have any practical nor even aesthetic values. I just like it that way.
Now that I wrote it, I can see why people complain when I don't go get what they want myslef.