Question: What is the proper way to claim a discarded tile?

Answer: A player must clearly verbalize their intention to claim a discarded tile. Acceptable phrases include “call,” “I want it,” “I’ll take it,” or variations such as “wait” or “hold.” These verbal cues signal to all players that the discard is being claimed or considered. This important step helps prevent the next player from prematurely picking from the wall, especially if the player making the call is not next in turn.

Source:  Mah Jongg Made Easy 2024,  pg. 15, para. 1