My sister was young and it was her second child. I think she rewarded his grunts so he never had an incentive to use words.
He turned out fine and will graduate from Savannah State in the spring.

I think kids at this age will only say what they need to get food or attention. If they get what they want by crying or saying baba.. why say more words?

There are a lot of great suggestions in here.

My 2 cents.

Keep talking to him

Keep the toys turned off except for the one he is playing with

Introduce a new word every day. If he is getting apple juice dont let him get away with just saying juice. Say apple 5 or 6 times and try to get him to repeat it before giving it to him

You can sing. Singing is a great way to teach kids new words and numbers.

Cheer him on, say thank you, please, etc.... these little rewards seem to work with young kids.

Dont put him in a room and force him to play. I would be terrified if my mother did that to me. It prolly feels like punishment at that age. Play with him in his room, once he gets going you can get up and leave the room.