Franklin (Dethras)
From Tardis Wiki, the free Doctor Who reference
Franklin was a chimpanzee who suddenly appeared in a submarine when its crew went missing. He started to speak. The Fourth Doctor theorised this was because of the close contact to Romana II and him. He was one of Dethras' initial experiments and when Flague found him he used him as a hostage. He escaped with Romana and decided to explore the universe in the escape pod. (AUDIO: Dethras)