I was reading my bit of grammar for the morning before church and I passed over this quote:
We pass on to the Article, on which there is not very much to say, since in all essentials its use is in agreement with Attic. It might indeed be asserted that the NT is in this respect remarkably “correct” when compared with the papyri.
James Hope Moulton, A Grammar of New Testament Greek, Volume 1: Prolegomena. (2d ed.; Edinburgh: T. & T. Clark, 2006), 80.
I like the way Moulton makes this statement. I think that by placing “correct” in quotation mark, it shows that he is quite aware that Hellenistic Greek isn’t simply poor greek or incorrect Greek, but it is only a different Greek from a different era. Moulton recognizes that the differences between Attic and Hellenistic are not a matter of right and wrong.
The various dialects of English deserve such a treatment as well, though I doubt it will happen from the general population. The way I speak is correct, the Brits speak wrong, those inner city people speak wrong, those Southerners speak wrong.