 The runes on the helmet worn by the Mouth of Sauron, when  transliterated, say "Lammen Gorthaur". Lammen means voice, and  Gorthaur, which is mentioned in the Silmarillion, means Dread  Abomination, another title by which Sauron was known. The complete  phrase, "Voice of the Dread Abomination", identifies the speaker as  the Mouth of Sauron.