You're allowed to declare your hand, too. At least by Grosvenor rules. All speech play goes. You do need to actually be involved in the hand at the time, of course.
lol... really??? i thought the hand was dead if you turned over the exact hand declared... when did grov. change that rule...
Quite a while back, and for the better at that. I really don't see that it adds anything to the game by allowing people to say whatever they like but then declare their hand dead if they call it true. It's up to you as a player to decide whether the truth is being told or not.