Joanna says "Hi Baby"

I've been trying to get Joanna to recognize that there is a baby in Mama's belly. Here is my feeble attempt:

Mom: Joanna, there's a baby in Mama's belly.
Mom: Joanna, What is in Mama's belly?
Joanna: (blank stare)


Yesterday, my newest attempt was humorously successful:

Mom: Joanna, there's a baby in Mama's belly.
Can you say "Hi baby?"

Joanna: (Looks at Mama's belly and waves) "Hi baby!"