In these days of employers' unease (to put it lightly) about the levels of "literacy" of those seeking jobs at all levels, isn't there a chance that by not pointing out the grammatically correct way of expressing oneself, we are sending out mixed messages to students of all ages? I don't leap on mine from a great height when they say "we was" instead of "we were" but I do make sure they are all aware of the grammar involved. Thing is, grammar and punctuation have not evolved simply to annoy, they have evolved to help us make our thoughts and opinions as clear as they can possibly be with no room for misinterpretation. It is even more important as we become more global and are communicating with those from other countries who may well have learned our language using all the rules and regulations correctly, that we are able to be quite clear in what we are saying. Dialect and accent are integral to our culture, I admit, but there is no reason whatsoever why we can't ALL be taught the grammatically correct way of speaking as well as writing, so that we can choose how to communicate most effectively depending on the audience and purpose!!!