Siri for iPhone 4, is that possible?
Siri on iPhone 4 is not supported, see which devices are supported here. On the other hand, Siri on iPhone 4s is available, which is the big brother model of iPhone 4 is, and the explanation of why siri iphone 4 is not supported, is that some of the secret of Siri comes from the company Audience EarSmart technology that is built into the A5 processor in the iPhone 4S.
Many iPhone 4 owners have enviously looked at friends with an iPhone 4S who are able to use Siri voice assistant. On the surface, Siri really a piece of software, but the reality is not quite like that when examined more closely - the explanation for why the iPhone 4 does not have Siri functionality is the processor that does not have the built-in technology required to get Siri to function optimally. You can read more about it here: CNET.com.
The company Audience, delivered a noise reduction technology to Apple, which is called EarSmart have in connection with an IPO announced that noise reduction is built into the A5 processor that is built into the iPhone 4S, which makes it possible to use Siri.
So in other words, the iPhone 4 has not the necessary hardware that allows Siri to function on the iPhone 4.