I'm a little late to this thread and can't sleep.
I used to help out at the schools Special Ed class when I was in Middle School.
Short story :The classroom I volunteered to help in had kids that can't or never will progress... Ever. The way I see it, it was a program set up to fail them and give the school more easy money. And the teachers an easy paycheck
Long Story: Some of the fully disabled kids were in wheelchairs, only a couple of them were walking. I think only the wheel chair kids had diapers on (I don't fully know).
I honestly felt bad for them! They were brought to a school against their will and the Teachers [If you can call them that] sit back and it's an easy paycheck for them. Very rarely I ever seen the teacher try to teach them to speak. It's either 1 of 3 things that the teachers do.
1: Put on a very brainrotty YouTube video.
2: iPad them and they shut up.
3: Ignore them and they check their social medias.
It's a very fucked up life and system for them. 12 years of schooling that doesn't help (and a waste of taxpayer money) then straight to a nursing home or something similar...?
My point is: I would like the teachers to at least try to teach them to talk. There are success stories out there.
Hope this helps.