In the "dim and distant" we traveled little and so many local dielects were created. We tend to mimmic the people who had power and so we have quaint customs like "Queens English". As the people mixed with one another these differing forms of the same language became known as quiloquialisms (pardon my spelling)which vied for popularity at different times and different people. This is not fixed in a stagnent state, much as my teachers would wish it was!
Individual people may be judged by whichever standard you wish and be judged as failing, but a group cannot. Once a group sets a new rule in place it becomes real so that weather I say "Youse dissi'n' me?" or enquire as to your "legitimacy of parentage" you can understand the meaning. That is the purpose of language and if you do understand it, it is succesfull!
Not that I am an expert ...... any more than you lot
BTW Scump "Yee tee" means "you too?" in Geordie ..... (ducks & runs)