habbibu it's about clarity in teaching. What hope have our children got if they are being taught one thing and hearing another? There's no harm in playing around with language when you already know the ground rules, but it really winds me up when, for example, children's TV presenters cannot use the language properly. I think there is a big difference between colloquial dialect and bad grammar.
The majority of our language has its commonly accepted rights and wrongs - as anyone who has sub-edited a newspaper will know from the complaints that roll in the minute one of the rules is broken!
There's always room for evolution, of course. And for experimentation. But I'd prefer that it did not get in the way of learning, particularly at primary school age.
Also, there's a vast difference between people using their own dialect or experimenting with language, and sheer ignorance. I think the latter covers most of the issues raised on this thread (unfortunately).
My name is Casper and I am a trained pedant .
P.S. I always recommend the Guardian Style Guide to struggling colleagues. But it's worth remembering that while some rules are widely accepted, a style guide is just that - a guide to the style of writing a particular publication chooses to use. I have struggled with some newspapers' style over the years, but had to use them in the workplace. Thankfully I am not in that business any more, and will no longer have to write "swop" instead of "swap".