Dear God, Mr P, cryptic as ever (I think!) you have lost me completely!
One of the posters above made mention of kids always having had their own lingo; I accept this, but itīs not the same thing at all today because the flaws have spread to the entire culture, regardless of age and, Iīm afraid, educational achievement too. As an example: one of my sonīs past girlfriends is a teacher and, having reached that degree of education, I would have expected her to live by what she had been taught. However, the little matter of all right versus alright came up and she, teacher that she is, could not accept that using the incorrect form was something that she should have risen above.
They are no longer together, but that had nothing to do with it, I believe...
I, too, as a silly little boy in the 50s thought it clever to emulate (probably badly) the language of jazz musicians as one imagined it to be from a UK perspective; Mr James Dean had a lot to answer for as did Mr Mumbles himself, Marlon Brando, both adding further confusion. But, and the big but and point is this: for examination purposes, for jobs etc. one always elected to use the best standard English which one could summon; this does not seem to be so today, where even television news programmes are spoiled by badly written captions. (I hate the use of captions on TV: how often has the golf ball fallen into the caption instead of into the hole on the green?)
Evolution of language is one thing, but wilful murder is another thing altogether.
Ciao - Rob C