I usually don't talk during a game when someone else is playing. Unless I'm in a party setting like when my friend brought DMC3 the day it came out and we took turns playing it and couldn't beat smurfing Cerberus... We had a good laugh then, especially when Easy mode was unlocked. We also chat during some survival horror series but its more when we play as a group. "Go in there!" "No, open the door" "Did I hear footsteps?" It makes some of those games scary fun, especially when the guy controlling the character squeals like a girl when something happens.

I'm a story whore so I don't usually like people chatting when I play but I usually don't play during times when people are around. Though I do have a bad habit of speaking out loud, my internal monologue about my thoughts on the game.