The reason why Whit has changed his voice is because he's a Timelord who was exiled to Earth (like the 3rd Doctor) because of his beliefs in Christianity. Using a fob watch, He was able to live a normal human life. He used Timelord technology to slowly take human tech (such as the Environment Enhancer) into pseudo-timelord tech (The Imagination Station, Room of Consequences, Inspiration Station) in an effort to subconsciously reclaim his heritage.
Because, unlike the Doctor, he can control his appearance, he looks pretty much identical in all three regenerations. When he was critically ill in his first regeneration, the Hal Smith incarnation, he found his fob watch in Israel, where he remembered his life as Time-Lord, and so he used it to regenerate into the Paul Herlinger Whit. Later, he regenerated into the Andre Stojka Whit

What are your crazy AiO therories?