Taken a bit too literally...   We abide by the ol Spades rule, "No talking across the board."

Oooh but quite a bit of trash talk gets slung in all directions, and the ruling debates are certainly epic.  The social interaction that we love out of those types of games is still very muchprevalent.

Being completely unable to talk during the game would not only ruin the feeling of being on a team, but it would ruin the social aspect of playing a game together. It would also make it harder to follow the rules regarding duplicating spells. 

And, I will add, when a move is made by two players on the same team, completely in synch, with zero communication other than the circumstances on the board...    It makes it that much sweeter.  Aaand the other side of that sword hurts quite a bit, too..  Like Yosemite Sam trying to keep the expletives at bay.  Oooooggghhh!!!