On ''what there is''

Not to be prosaic or anything, but languages constantly evolve. Differing dialects evolve among different groups of speakers. When enough changes happen and these various dialects become unintelligible to the other, the new dialects are now officially different languages. There's no right or wrong here. One language is not better or more pure than the other. Think of Latin. Think of Latin's descendants French and Italian. Think of Modern German and Modern English.

The evolution of language does not contradict the existence of these 2 levels but is a consequence of it .....

Where is Chauncey the gardener when we need him?

@steamerdude

Rather than contribute… I think that he prefers to watch?

I will react to two posts and then stop my contributions.
First about ''grammar wonder''. As is know American 
make difference between their ''great'', ''mediocre '' and
''worthless writers''. But they all share the same grammar.
This of course apply for all ''nations'' which obviously must
have ''national literature'' in order to compete with other
nations. In the past we also have had ''national science''
with the question which is the best: German, English,
Russian or American. 
Now look at the kids all over the world. At the age of 4 they
speak each language  whatever. How long you think an
English teacher will need to learn Chinese or Japanese?
I am not sure but think that Chomsky called ''language capability''
as, say, gift of mother nature. Do 4 years kids know what grammar
is ? This capability seems to work till the age of 12 (?)