He speech was indistinguishable from that of a human, complete with inflections and emotions. However, his facial expressions were extremely limited.
Edward Repple was created on Katuria and programmed to believe he was Shade Vassily, a deposed tyrant of Katuria. He was sent to Earth together with Aske who was to play the dual role of his jailer and bodyguard and who did not know of his true identity either. Repple's legend was that he was the deposed monarch of Dastaria, a country near Russia he invented.
Repple and Aske met the Ninth Doctor and Rose Tyler in London in 1924. When Melissa Heart tried to kill the Doctor believing him to be Vassily, Repple easily persuaded her that the Katurian hiding on Earth was he and not the Doctor. Aske died defending Repple's life.
However, the Doctor deduced from the constant ticking that he heard in Repple's presence that Repple was actually a Clockwork Mechanical. The Doctor proved it to Repple by taking his face off.
With the Doctor and Rose, Repple stopped the real Shade Vassily from escaping Earth and destroying London. In the process, Rose was nearly crushed between two cog wheels inside Big Ben. Repple saved her life by using his arm to jam the wheels, but lost the arm in the effort. His arm was replaced by the Doctor, who used an arm from one of Melissa Heart's clockwork knights.
Though he was an android, Repple felt human. The Doctor told him that he didn't have to have blood to be human and encouraged him to enjoy life on Earth. Rose Tyler asked him to visit her in eighty years time. (PROSE: The Clockwise Man)