Adanedhel posted this as a comment in the Blog of Mazarbul but I thought it useful enough to add here where more people might read it.

A while ago, I started compiling a list of Tolkien’s works in various languages (whether the books were published or not) so that it could be used by collectors to find titles in those languages and use them for search on the internet (or just to see how ‘The Fellowship of the Ring’, for instance, would sound in different languages). At first I started only with the Middle-Earth related books but now I decided to expand the list. It is far from complete, but I’m working on it. You can take a look at it here:

I’m also working on collecting translations of the Ring Verse and I’ll soon post it.