Hola! Ñ...а Ñ...а Ñ...а. Translation: Hi! Ha ha ha.
Welcome to the languages thread! Everything language based and how we communicate using a beautiful language will be talked about here. Grammar of languages, best language, translating between languages, and anything that can somehow be related to a language is welcome here.
Now for a few questions to start off the thread: If you could learn 1 and only 1 language what would it be?*
What language do you believe is the most useful to learn and which will be the most useful in the future?
*In addiction to your first language. If you know more than one language than you can still pick another.
To illustrate the subjectiveness of its formal definition (which, yes, you posted):
The reason why I linked it is because it describes the older version of Spanish: that of the central region. That is, indeed, at least an attempted confirmation of what I said I hope. Also, it says that the term can be used to differentiate from Latin-American Spanish (as in, influence by such culture to insinuate a need for individualization in nationalities).
I am still looking for a confirmation of the Venezuelan/Argentinian effort I had mentioned through the Internet.
And I believe this confirms my final point. It says something along the lines of "The language is referred to as castellano, seldom Español." And as you'll notice, Wikipedia's claim of the national language is de facto. I'm not sure if that's enough but I will keep looking if you would like more.
If there is anything I missed, feel free to point out.
I dunno, Salvidian, I remain unconvinced so far. I reckon it's a question of nuance we are looking at, of "focus" as that person in their dissertation (Hye-Yoon Chung, in the first link you gave. I've honestly only glanced over bits of it) calls it. Not of distinct (forms of a) language(s).
But I guess at this stage we can just gracefully agree to disagree Cheers.