The Streets Of Hammerfast
Table talk is any out-of-character conversation that results in an exchange of information that wouldn’t be available to a player. If you want to discuss something with another player, try to discuss it in character. (You don’t have to use a funny voice, or even say it in the first person, it can be as simple as “Hans von Maulinghaus yells out ‘which one of these jerks should I pound next, boss?’”)
Questions about rules or about what kind of information a character has (“what do I know about kobolds?”, “how does charging work?”) aren’t table-talk, because they have to do with the mechanics of how to play the game. Even the dumbest character understands when he has cover, when he has combat advantage, etc.
Stuff that should be avoided is extensive out-of-character battle planning, discussing how many hitpoints specific enemies have left, basically anything that the characters wouldn’t have access to in the game world.