Ishtass, from Ultima Underworld
When the Avatar met him in Ultima Underworld I, the hero was surprised that Ishtass was capable of speaking English, although he admitted that he had to concentrate for it. This of course made him an outcast from the differently-colored Lizard Men population, and Ishtass couldn't offer much help with Lizard Man vocabulary, as it went against certain oaths.
He however could tell a lot about their history, and revealed that he was searching for a scroll once possessed by the great Ossikka. Getting the scroll for him, Ishtass gave the Avatar the only WIS-Rune Stone available in the Abyss. He also revealed the fate of the sword Caliburn and where to find one of the pieces.
Later, he went deeper underground, like all the Lizard Men, when the Abyss was destroyed.