I'M THE VOICE OF SIRI.
Apple
used the voice of a woman named Susan in the apple products, Susan had no idea
who had used her voice in Siri , then one day she began to arrive mails from
people who had used iphone asking "isn´t this you?”

Apple won't confirm it.
But susan says she is Siri.
Professionals who know her voice, have worked with her and represent her
legally say she is Siri. And an audio-forensics expert with 30 years of
experience has studied both voices and says he is "100%" certain the
two are the same.
It is
strange that apple would have said anything to susan that millions of people
were going to have the voice of her on their cell phones.
http://www.cracked.com/personal-experiences-2108-i-am-siris-voice-4-bizarre-realities.html
http://edition.cnn.com/2013/10/04/tech/mobile/bennett-siri-iphone-voice/