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

Answer: A player must verbalize their intention to call a discarded tile. They can say, “call,” “I want it, “I’ll take it,” or any variation thereof such as “wait” or “hold,” as long as they verbalize their intentions before picking up the discard and to prevent the next player from picking a tile.   

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