Lyrics really mess with me working, although if its in a foreign language I find it a little bit less distracting. I had a friend that had a Pandora channel for instrumental movie scores that he would use when writing novels. But after a while he realized that upon re-reading his stuff he would know what was playing when he wrote certain parts lol. The epic battle scene music from LotR would change how he wrote compared to just flying over the shire.