Siri founder leaves Apple

The co-founder and chief executive officer of the company behind the iPhone 4S's flagship 'Siri' feature has left Apple, according to anonymous sources.

Dag Kittlaus co-founded Siri, a company concentrating on speech recognition technology, in 2007. The company's primary product, Siri Assistant, caught Apple's eye when it was released for the iPhone - leading to the company's acquisition in 2010.

Fast forward a year, and the iPhone 4S is launched with Siri - now lacking the Assistant suffix - as its headlining feature. While it helped bring Siri's technology to a wider market, it came with a dark side: the removal of Siri Assistant from the Apple App Store.

There's no denying that it was a mercenary move on Apple's part: by making Siri exclusive to the iPhone 4S it gains a way to convince existing iPhone 4 owners to consider upgrading to the externally near-identical handset, but it leaves those who relied on Siri Assistant high and dry.

As Apple's own advertising shows, Siri - and, by extension, Siri Assistant - is a handy tool for the partially sighted. The official iPhone 4S advert shows just such a person reading a Braille book when a text message arrives, which is read out and then replied to via the Siri functionality of the iPhone 4S.

That same functionality was available to the iPhone 4, right up until a week after the iPhone 4S was announced - at which point Apple switched the servers to only answer queries from the iPhone 4S. Even those who have jailbroken handsets and can install Siri on their older devices are unable to actually make use of the service that they once relied upon.

While sources speaking to AllThingsD claim that Kittlaus's departure from Apple is amicable and has been planned for some time, the timing is interesting: leaving so soon after the move to iPhone 4S exclusivity for his pet project suggests that Kittlaus isn't happy with Apple's somewhat cynical move.

Other Siri executives are expected to remain at Apple.