I'm trying to catch up here.
I think to some extent we're never going to agree on the linguistic thing. I believe that if you are fluent in language A in linguistic environment B, your brain will be wired to do better at language B than if you had the same degree of learning of language B without having the knowledge of language A. I think that you think children learn the environmental language best if it's their first language.
But at the same time, I think we agree in terms of whether it's ok to put a child in an exclusively signing environment, although possibly for different reasons. I don't believe in monolingual education except in the case of those incapable of learning a second language, and to be that mentally impaired, you'd need to struggle in your first language. You, I think, don't like it because you don't think a sign language should be what I'll call a first language.
Either way, I think we agree that BSL shouldn't be a child's only language unless they are incapable of learning English or other regional language. But then I struggle to see how a child in this country could be reasonably/properly be educated with access to the internet, so whatever their primary language, they need English.
Incidentally, as a young child with glue ear and spending a lot of time alone reading, I know from looking back at essays I wrote as a child that I had a vast vocabulary of words I didn't know how to pronounce. I worked that out later, but the vocabulary was there.
That being said, I'm mother tongue English, having started French at the age of about seven and still partly thinking in it (which I think you'd agree doesn't Frenchify my English) and having started to teach myself German from a French textbook whilst still at primary school. I went to a secondary school where I studied French, German, Italian, Latin, Ancient Greek (Homeric, Attic, Doric), Biblical Greek. I remain very visual with languages and remember vocabulary better if the language is written in an alphabet I'm fluent in, whether or not that's the alphabet usually used in that language.
I have very, very strong views about issues relating to university education in the UK, which map onto my views about schooling. I cheer on today's youngsters when they demand a fairness, no longer willing to put up with a lot of what we did. In relation to my undergraduate course, the entrance requirements were unfair, some of the subjects very badly taught, the library resources not good, the exams didn't map onto subjects as taught etc.
So ironically, I think that one thing that students in general can benefit from is universities reviewing what adjustments they make for various disadvantages, because my gut feeling is that mostly they result in general improvements for all students. I also don't believe that having parents wealthy enough to send you to the 'right' schools should give you an advantage at university entrance. Example of that:- it's now the case that it's no longer rare for what I'll call 'posh' schools in England that are, by virtue of not being state schools, not bound by the national curriculum, to enter their pupils for completely different exams. I don't mean different subjects, I mean different qualifications. Some universities appear to treat those as worth more.
There is so much bias in our education system, most of it, I belive, social. For example, I believe that a large part of educational disadvantage experienced by some racial groups arises from being more likely to be brought up in certain deprived areas.
Where I live, there are over a dozen state primary schools I can walk to without hurrying in under half an hour. There are loads of secondary schools, state and private within either short walk or short walk plus one bus travel from where I live. Massive difference in catchment. Did you take your child to the right place of worship for a year before admission to that high-performing state school? Could you afford at least half a million for that house in a tiny state school catchment area, or do you have a large income for that school with a wider catchment area but fees? If not, your child will go to the state school other parents don't want their kids to go to because it's got fewer facilities and fewer wealthy parents willing and able to donate to school funds etc.
So for me, if disabled people, including deaf people, want a better deal for their kids and greater inclusivity, the most important thing to do is to campaign for general fairness.
But then I've also expressed the view elsethread that for decades now I've been in favour of the model of education that's about clusters of schools or 'houses' within schools, with shared facilities and activities and separate facilities and activities. I think that that can work for loads of SEND children as well as working for children like myself that had a primarily single sex education but with shared facilities as well. Badminton? Pop next door to the boys school. Woodwork? Pop next door to the boys school. Oh hello, there's some boys there that want to join our music group. And the dance class.
And as I write that, I suppose that that's exactly what's happening with my nearest Deaf 'unit'. It's got its own doors and classes, but it's on the same campus as the other 'units' and 'schools'. You could teach the Deaf pupils no English at all and they'd still pick it up in the playground or on the bus, just as lots of immigrant children from non-anglophone countries pick up English in what seems like no time at all.