Every claim on a discard must be verbalized (3.6.1); Say "Chi" to chow, "Pung" to pung, "Kong" (or "Gang") to kong, "Hu" to declare mahjong, and "Hua" when taking a flower replacement (3.6.1); Players must not call out the names of tiles when discarding, and are forbidden to discuss, gossip, or c...
Why people argue about this
People often assume that they can whisper their calls of tiles when discarding, thinking it's just a minor oversight in the official guidelines. However, the rule explicitly forbids discussing or gossiping about the tiles at all, which leads to misunderstandings and arguments over whether players are breaking this crucial aspect of the game.
