But surely children learn language from speech just as much as formal lessons? What is the point of a teacher teaching the correct grammar in a lesson but then undoing that work by speaking incorrectly at other times?
I agree with you actually. Children learn from reading and listening. My husband and I are always careful to express ourselves correctly when we speak to / in front of our kids. It seems to be working - my 4 year old speaks so nicely.
*I grew up listening to and speaking three different dialects of English in different contexts, two of them 'non-standard'.
Later, I somehow managed to write an entire PhD thesis in standard English without a problem.
As an adult I can happily switch back and forth depending on the context I am in and to whom I am speaking. I am by no means unusual in my ability to do this.
You clearly don't know a great deal about language acquisition if you consider the use of non-standard forms of English being spoken around children to be a problem.*
Yes, YOU can. Many can't. You have a PhD, as do I, but this of course isn't representative of the majority of society. I'm an English teacher and many children I teach write with the same grammatical inaccuracies they have in their speech - which are likely reflective of what they hear. I'm not saying I speak like I do in my academic writing - that would he creepy - but I certainly speak to my students with a reasonable level of standard English.
For many children, school is the only place they come across standard English. If they don't hear standard English spoken at home, and don't read much, they depend on hearing it from their teachers. A person won't be able to 'switch' if they have nothing to switch to!
However, I did vote YABU. This is because teaching is in a major crisis right now. Pay is poor, workload is horrific, and there is a massive recruitment and retention problem. Teachers have been striking, yet many parents have criticised them for this. Well, if you want teachers with a decent level of standard English, I'm afraid the career needs to be more attractive.