As Aveline implies, more socialising could slowly help.
Have they always been home-schooled, or just since Covid?
When I was working as an Ed. Psych. we had a wonderful Speech and Language Unit which no longer exists.
I'm still in touch with the teacher in charge of the Unit and next time I speak to her will ask her advice,
She's my age (early 80s) and has health problems so is no longer active in this field but has a wealth of experience.
Scottish political mess. Is Devolution working?