@rmagere: Translations of books are meant to be combined with the original, but sometimes the one who adds them to Goodreads don't do this.
I combined your example, Nudi e crudi with the original, The Clothes They Stood Up In. You should now get the most popular tags from all editions (as long as you have the tags correctly mapped in the plugin-configuration).
To combine books on Goodreads, unless you add them yourself, ask in the librarians group
Or if you know of a lot of books that needs to be combined, maybe become a librarian yourself? Anyone with a certain number of books shelved (50?) can ask to become one. For tips on being a librarian, you can read the librarian manual