What the tablet says, in the 1880 translation. Tablet XI opens: "1. (Izdubar) to him also speaks even to Xisuthrus afar off: 2. O Xisuthrus, 3. (why) dost thou not again (to me) as I (to thee)?"
Two people, in line 1. "Izdubar" is the epic's hero, who has travelled to find the flood survivor; "Xisuthrus" is the survivor, who then tells him the story.
Why the names differ from today's. The cuneiform sign-group for the hero's name could not yet be read, so Smith gave it the provisional value "Izdubar" and identified him with the biblical Nimrod, an identification no longer made. The modern reading is Gilgamesh. The survivor was called "Xisuthrus", the name given by the Babylonian priest Berossus writing in Greek in the third century BC, and also "Adra-Khasis"; his name in the epic is now read Utnapishtim. So the 1880 text is a historical document of the decipherment rather than a current translation: its content is sound, its names are of its decade.
⚠️ A source we hold states this differently, and the difference matters. The 1915 International Standard Bible Encyclopaedia, in its article Deluge of Noah, writes that "The human hero of the account, corresponding to Noah of the Bible and Xisuthrus of Berosus, is Gilgamesh." On the tablet itself, Gilgamesh is the one being told the story, not the one who survived the flood. The encyclopedia's text is public domain and is left exactly as written; the difference is stated beside it rather than inside it. ⭐ Note that ISBE has the right city, it places the hero at "Shurippak", which is indeed the flood survivor's city in the epic, so the error is the name, attached to the right person's details.
Sources: Smith, Chaldean Account, Tablet XI, column I; ISBE 1915, "Deluge of Noah".