Apple introduced Siri along with the iPhone 4S. And with the iOS 6 release, Siri was made available for the iPod Touch (5th generation), the iPad 3, the iPhone 4S and iPhone 5. 
Not Finding Siri on an Older iDevice?
Older devices do not have Siri. So if you are wondering why there is no Siri on my iPad 1 or 2, you simply won’t find Siri on the iPad 1, iPad 2 or iPod Touch (4th generation) because Apple does not support these older devices with Siri.
Related:
- Some Siri Errors/Problems can be fixed by resetting network settings
- Siri not working – troubleshooting
- How can you teach Siri to pronounce your name correctly?