To place a call by speaking

Touch Voice Dialer in the Applications screen.

If you have a Bluetooth device that supports “voice-recognition” or “voice dialing” you may be able to open Voice Dialer by pressing your headset’s main button or in some other way, and dial by voice using your headset. For details, see the documentation that came with your headset.

Say “Call” followed by the name of the contact or say “Dial” followed by a phone number.