That's what Wikipedia tells. I had no clue where it came from. Of course it's not unheard of the big companies like Apple buy their best ideas from elsewhere.
Siri started life running on Android and iOS. They took it down when Apple bought the company two months after launching. So if you blinked you might have missed it =)
I think the android bits and some of the staff formed Kuato after Apple bought Siri. I interviewed for a gig there back in the day, but I landed at Linden Lab instead.