sigilion
Taking, as an example, the final sentence of your first paragraph: "Brobdingnagian, deleterious, autodidact, loquaciousness... are these really such strange vernacular?" we find a sentence that is grammatically incorrect, with the singular form of vernacular. Assuming a typographically damaged plural does no good, as these words are not vernaculars. We do no better with the assumption of an elided indefinite article ("are these really such [a] strange vernacular?") as the answer is trivially yes, attempting conversation using only these words (Brobdingnagian, deleterious, autodidact, and loquaciousness) would be an exercise of Cnutian futility. As the recurring problem in finding meaning in this sentence is this definition may I suggest that perhaps the primary issue is in the choice of words? I would suggest the substitution of "words" in place of "vernacular", as this recovers a perfectly sensible rhetorical question. Perhaps, in keeping with the theme of subtle distinction in word choice, "obscure" could be substituted for "strange", signifying the strangeness is rooted in rarity of use, rather than e.g. etymology.