I remember the last babies we had around here, the twin boys of my son.
Being twins they just did the mama, dada stuff and kinda clammed up. They had their own language of a type. I was teaching them baby signing. Their mother was working with an abbreviated system of advice given her by a speech therapist and doing the mouth shape sounds with them everyday.
Their hearing was checked.
Almost 5yo now, they chatter like squirrels. But it was a concern for a couple of years.
Remembering, their first really good words were of wanting a thing. They were very interested in the world around them but it was mostly wanting something they couldn’t reach, weren’t allowed or dangerous.
Specifically they turned the corner by saying “my toy” or “cookie, please".
Mother worked very hard, as we all did(even the older kids) stretching out their sentences to a “can I have a cookie, please “ kinda thing.
I felt like we were working with Apes for awhile. They did not want to give up their secret language. In preschool they went to a speech therapist a couple times a week. She had to separate them to get very far. They are Pre-K now. And it’s all behind them.
I still sign with them daily. I think they are the best signers in the bunch.