Ds is 17 months. He says very few words 'mama', 'Dada', 'no' and his name. He does seems to understand some of what we say and will sometimes follow simple instructions (eg if we ask him to bring a book and point at them, he will pick one up) but if we mentioned something more abstract (eg asking him
to bring shoes when he can't see them) he wouldn't respond.
Most of the babies we know have much better speech and understanding than him.
I think his hearing is fine. Should I be worried?