My toddler (20 months) just doesn't talk! He literally understands everything but doesn't talk.

Sounds very similar to mine. He’s also 20 months and can’t even say mom and dad. But very talkative in his own language. I got a referral to a speech therapist during his 18 month regular checkup at polyclinic. But I’m still waiting since he understands so many things. Hope he’ll speak soon. 😌