Question about babbling for those with late-talking children

[Biscuitrules]

DS2 is 3.3 yo and has a diagnosis of social communication disorder. He has good understanding of receptive language (e.g. follows instructions, nods yes or no to answer questions) but no expressive language. We've had some input from SALT but to be honest I haven't found it that useful.

I have noticed recently that he has stopped babbling and spends a lot of the day silent - just occasional vocalisations to himself when playing. He did use to babble as a baby, within the usual age range, although the range of babbling was fairly limited - mainly vowel sounds, plus dada, mama, but it never progressed into other consonants and he has never copied us making sounds (although he will copy physical actions).

One hears stories about late talkers where children aged 3 or 4 will suddenly start talking. I am curious what preceded this? Did they babble constantly and then it turn into speech? Or did they babble for a while and then go silent and then speech suddenly emerge?

My concern is that it seems to me that he has "finished" his stage of babbling, developmentally speaking, without it having progressed into speech. One reads how babbling helps babies develop the oral motor control necessary for speech. However if he is not using any of these pathways surely it will be very difficult for him to talk, like any of us if we have not practised using a muscle group (e.g. if I try to use scissors left-handed).

Any anecdotal data much appreciated! At present I don't know whether to be concerned.

My son was a little over a year when he stopped babbling. I had him assessed early and he learned baby signs. He didn't have many words and mostly just uttered like a dolphin. As he learned to speak (with a lot of early intensive individual speech therapy) he would sign and say words. He mostly dropped final constanants. Eventually he stopped signing as his words grew. Now at 14, his siblings still know the baby signs we learned (add made up), but he doesn't even remember not speaking.

My friend has a child also speech delayed and he is 3 years older. He didn't receive speech until kindergarten and only in group settings. It is still difficult to understand him.

If I was you I would try and see a really good speech therapist (unfortunately you might have to pay for it)
We saw the NHS salt from when he was 3-5 with vertually no difference, it wasn't until I started taking him weekly to a great private therapist that anything changed. He's fine now. I would say the earlier you do it the better

My DS is 3.2 years old and we have been told he has some form of social communication disorder. We have mainly been dealing with NHS SALT but it's not helped much, I completed the Hanen course more than words which I found really useful. I have been given the impression that if it's a speech delay then this sudden use of language is common but as it's a disorder you normally wouldn't see that?