What is Siri on the iPhone?
If you have the iPhone 4S or iPhone 5, these models of the iPhone have a feature called Siri which allows you to talk to your phone and use your voice to control the phone
Siri lets you use your voice to send messages, place phone calls, schedule meetings, set reminders, and more.
You can ask Siri to do things for you just by talking the way you talk. Siri understands what you say, knows what you mean, and even talks back.
Siri also enables dictation. Instead of typing, tap the microphone button on the keyboard, speak your words, numbers, or sentences out loud, and let iPhone convert your words into text. It’s easier to write messages, take notes, or search the web. Dictation also works with third-party apps.