Must is used to emphasize an action. That means to put some stress. The structure is similar to ‘Should’.
I must speak English.
I must take all the cookies.
I must give this bat to him.
I must go home now.
You must not disturb me. (with forceful voice)
You must listen to me.
You must talk to me.
You must speak in Urdu.
You must tell me this story.
You must do your homework.
In this structure, there is no questioning-style. So, ask the kid to work on simple and negative structures only.