Put three objects your child knows well on the table — a shoe, a banana, a spoon.
Pick one up and name it confidently but wrong: hold the shoe and announce 'this is a banana!' Look completely serious.
Wait for the protest. Whether it comes as a laugh, a head shake or the right word, accept it, look amazed, and ask what it really is. Then get one right so the game stays fair.
Correcting an adult requires the child to hold the right label in mind, notice the mismatch and produce the word — three operations at once. Humour supplies the motivation that flashcards cannot, which is why children volunteer words here they withhold when tested.