I believe that I may have discovered an undocumented voice actor in the game, but being that the voice is undocumented, I have no idea how to verify it. I've become convinced that Dringoth from the quest Keeper of Bones, is voiced by well-known character actor and director Kenneth Tigar. He's not listed on UESP's ESO voice actor page, and ESO is not listed as one of his credits at either IMDB or Wikipedia. I'm not sure how to prove or disprove it, but I'd love to know for certain. Check out the numerous interviews and TV clips on YouTube for instance, to hear his high-pitched and slightly raspy voice, and see what you think.