In friendly games most players still announce "check". However announcing "check" is not required under the rules of chess and it is usually not done in formal games (Just & Burg 2003:28). In algebraic chess notation, a checking move is recorded like any other move, except that a "+" is normally written after the move.

Can you win chess without saying check?

So, how do you win a chess game if you don't say anything – the simple answer is if your opponent's King has nowhere to move. The primary goal of a chess game is to trap your opponent's King. If the King can't move anymore, then the game is over. You don't need to say anything to win.

Why don't they say check at big tournaments?

announcing "check" needs to be forbidden in tournament play. It's unnecessary and disrupts people's other games. If you want to indicate to your opponent that they are in check , without saying anything, simply point to their king.