I went to hear a performance of Brahm's A German Requiem last night. It was very good, but it was translated into English, which is never a good idea. Still, the choir was game enough, and even though the translation itself was rather shoehorned into the music, they did what they could, and all things considered, did it pretty darn well.
Years ago, I attended a performance of Beethoven's Ninth that had the final movement in English translation, and it was just laughable...apparently, the translator was a frustrated pop-lyricist.