About those praising anything in use as good grammar, I would say that I may deal with "ain't" and "me neither" as part of some grammar, but that I have some problems with "I seen them two boys run out", and I would like to see what them free style grammar lovers sketch to make "I ate a whole nother apple" grammatically sound. Maybe dictionaries will show an entry with "nother: adj. additional".
I don't see any reason why dictionaries will not, in principle, end up having an entry for "nother" if enough people start using it.
After all there have been similar language mutations in English such as when "napron" became "apron" due to the regular co-occurrence of the article "a" leading people to think they were saying "an apron". This process is apparently called
rebracketing and it has also transformed "a nadder" into "an adder" and "an ekename" into "a nickname", and "al one" (all one) became "alone".
Guy Deutscher in his book The Unfolding of Language suggests three main ways in which language changes which are:
Economy: "Lazy" people reducing their speech until the words are worn down through use. Jonathan Swift was particularly incensed at the "lazy" people who pronounced these words without sounding out the final syllable: "What does Your Lordship think of the Words,
Drudg'd, Disturb'd, Rebuk't, Fledg'd, and a thousand others, every where to be met in Prose as well as Verse? Where, by leaving out a Vowel to save a Syllable, we form so jarring a Sound, and so difficult to utter, that I have often wondred how it could ever obtain."
Expressiveness: Due to the falling out of meaning of particular words or parts of words, some element is used to "beef up" the meaning of a word. For example, perhaps someone may add a whole nother "pre" to "prepared" to form "preprepared". Similarly, a weak-looking full stop at the end of a sentence may not have the sense of finality that a writer or speaker wants so that person may end up saying, "period!" to underline the point. And if that is not strong enough, "Period. The End." Or we may add an infix to "absolutely" such as "abso-bloody-lutely"
Analogy: A lot of irregular past tense verbs and plural forms have become regular over the years. Or indeed the aforementioned rebracketing where we overgeneralize a rule or perceive one that isn't there.