Ive never been or watched the actual chess tournament in person. I have this question. Is it appropriate to say 'check' or 'mate'? Or the player doesn't have to say that?
During a chess game tournament players are required to stay silent, no "check!". Only exceptions are: "I resign", "Draw?", "j'adoube", you can say "checkmate!" if you like, as the checkmate ends the game, so the "checkmate!" is not during the game.