Make phone calls and control music playback with Voice Control. (On iPhone 4s or later, you can also use Siri to control iPhone by voice. See the Siri section.)
Note: Voice Control and Voice Control settings aren't available when Siri is turned on.
Use Voice Control. Turn Siri off in Settings > General > Siri, then press and hold the Home button until the Voice Control screen appears and you hear a beep, or press and hold the center button on your headset.
For best results:
Change the language for Voice Control. By default, Voice Control expects you to speak voice commands in the language that's set for iPhone (in Settings > General > International > Language). To use Voice Control in another language or dialect, go to Settings > General > International > Voice Control.
Voice Control for the Music app is always on, but you can prevent voice dialing when iPhone is locked. Go to Settings > Settings > General > Touch ID & Passcode (iPhone 5s) or Settings > General > Passcode Lock (other models), and turn off Voice Dial.