It's complicated: many games use motion capture to get realistic movements, and overlay that onto character models with appropriate skins applied. Others use "rag doll" physics where the various parts of the body are individually animated according to the forces applied to them. Very few games use "live actor" video footage outside cut scenes (and they tend to be pretty dull games anyway), but live voices is the norm.
I'd suggest that you start with a specific games forum rather than a general software development one, and the two worlds don't normally overlap as much as you might think! Take an example like GTA V:
Development of Grand Theft Auto V - Wikipedia[
^] around 1000 people worked on that game and a relatively small percentage were software developers writing code.