How to turn off voice chat?

The Push to Talk Command is bound to the V  key on the keyboard by default in the PC version of the game.

If you don't like this binding, you can indeed change it to something more convenient. To do so, you'll have to (re-)assign a button, key or axis to the push to talk command as described in the following steps:

1. In the Main Menu, click on Options.
2. Click on/Select Controls.
3. Click on/Select Remap Controls
4. Click on/Select the Change button to the right.
5. Select/click on Menus.
6. Select the input device you wish your push to talk button/key/axis to be set to.
7. Scroll down until you find Push to Talk and click on the field on the right where (--- or a button/key/axis assignment is).
8. Once the binding window pops up, push the key/button/axis you desire to bind it.
9. Save your control settings when prompted to and you should now be able to only be heard when you push the assigned button/key.