Essorant wrote:A waitress at a restaurant atrociously asks "How is your guyses' meal?"! Someone at another table says "Aren't I clever?". At another table "I and her went to the dance..." . From another table "It was him...". The tables are full of bad grammar.
In all fairness, that is a bit of an exaggeration. Excluding slang and idiomatic phrases - and I'm going to contradict myself at the end of this post - grammar of most modern natives is normally "correct".
Essorant wrote:It is not because there is a lack of natural imitation among people, but because there is a lack of understanding and knowing better.
Knowing better? It's a facetious concept. I hate to say this again, but grammar is a tool to analyse language, trying to reverse-engineer a language from that is ridiculous. Also, "knowing better" is an extremely arrogant phrase, who says you know better?
There is also the fact that Shakespeare says things like, "I would have my dinner", which to me only makes sense to my 500 year later brain because I know what he "meant". It does not mean that it is ungrammatical or incorrect, simply that that form of expression is no longer in use. Or to take the infamous example, nice in its 2000 year history, will be familiar to Latin scholars as ignorant, all the way through French and English, meaning at different times, foolish and stupid, to its present day usage of pleasant.
Essorant wrote:I think an approach that says speakers shouldn't "think" about what is correct is very unhelpful.
Granted, for a non-native speaker, it must be annoying to hear that. But on the broader issue, this isn't a chicken and the egg conundrum, there is a definitive answer. Language came first, and language constantly evolves. Grammar came later as a way to analyse language, logical grammar was no in-built into homo sapiens, and then created languages from that. And we've been doing this for decades, hypercorrection affects us all. As Winston Churchill rightly said, "this is the sort of tedious nonsense up with which I shall not put!"
Back to the contradicting myself, recently, Irish people have begun to use "he was like" to mean "he said", and "he goes" to also mean he said. That is ungrammatical to me, and makes no sense. However, I have to accept it as a new idiom that has recently been introduced into the language. While I don't like it, and I will never use it continually (since I hear it so much, there is a strong likelihood I will use it sometimes), I have to accept it. It's possible that in years to come, dictionaries will include it as a meaning. And as I'm sure you know, we are not new to this, French te^te (head) is not derived from the classical Latin for head (caput?), but rather from what in classical Latin means pot (testa). They just didn't know better.