Language has always existed and will always exist.
The primary thrust of language is the perpetuation of wisdom and knowledge. This is achieved through the epics, myths, religion, and all manner of virtue-based creations. Religion, particularly, is a topic that propagates language and rhetoric: in essence, man has always sought to understand and relate to the divine. Man is soul and body, and that dichotomy plays out in our language and in our actions pervasively.
Vico's “New Science” seeks to articulate wisdom through the same means, but with an eye on the use of reason as a critical tool. He notes the “three theologies,” and seemingly postulates a pseudo-continuum of anecdotal/poetic to reasoned/rigid rhetorical force behind them. The fact is, that they all derive from the same root languages in terms. The debate over wisdom is a rhetorical one, but the words seem to be “the same, just different.” It defeats the purpose to historically gauge anything, because we've only rephrased what we know. We focus on the divine, on myths, or on ourselves but we never really do anything new, we just use new (old) words.
I agree with his observation that first the poets sense and then the philosophers intellectualize. Unlike other thinkers we've read, he doesn't give soul agency for evil to the poet, the philosopher is a needed interpreter and expounder of ideas. This, I assume, is what leads to his cyclical history.
I don't lend any real credence or ear to the rest of his example or specific prescriptions for word-use and forms, because, well it's 2013. I'm obviously more historically wise, hip, and with-it than he is… also, I'm not a student of rhetoric.
Sisto, Jordan. “Vico.” Literary Criticism and Theory. 1/31/13. <http://ablogbyvirtueofitself.blogspot.com/2013/01/vico_31.html>