There were several reasons for the departure, which was amicable and has been planned for a while, sources said. They included Kittlaus' family being in Chicago, a desire to take time off and an interest in brainstorming new entrepreneurial ideas.
Kittlaus headed up Apple's speech recognition efforts since his company was purchased by Apple in April 2010. He had been CEO of Siri since 2007.
Apparently, Kittlaus left Apple after the launch of the iPhone 4S.