If you use the voice dialing on your phone or Bluetooth. Go into Options/ Voice dialing/ and at the bottom you have the option to have the phone "adapt to your voice".
Instructs you to go into a quiet room and it automatically gives you a series of prompts of names to repeat, phone numbers to repeat, etc. Once completed it learns your voice reflections and stores them. Makes it alot more accurate on Bluetooth Voice dialing etc.