I suppose this is what happens when you spend your formative years buried in literature - it probably doesn't help that I mispronounce all sorts, as books make poor elocutionists.
I do worry that as we further and further consolidate our vocabulary that we lose the breadth and depth of thought that nuanced words provide... so did Orwell...
2. Never use a long word where a short one will do.
3. If it is possible to cut a word out, always cut it out.
4. Never use the passive where you can use the active.
5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
6. Break any of these rules sooner than say anything outright barbarous.
-- Orwell, "Politics and the English Language"
The thing is, note "will do" in (2). There are many cases where a short word really won't do, lest you lose nuance and meaning.
Although we might get a bit of a thrill from talking over people's heads, it doesn't really mean much of anything. And all it takes is one misuse -- for example, calling Brobdingnagian a neologism -- and we tear ourselves down more than we could hope to build ourselves up.
Agreed - never use a complicated word when a simple one will do - but you either have to turn verbose or lose nuance, as we're not talking synonyms, but words which have meanings distinct from some of their more commonplace counterparts.
No thrill, I just hate taking the colour out of language, and I like to share words far and wide, so they don't drift into oblivion, along with the thought and meaning behind them.
It's true that there are sometimes nuances lost in the conversion from large to small, but there is far more nuance lost once your partner doesn't know what the hell you are saying. For you, Brobdingnagian might have some special nuance (I'm picking on that word because it is ridiculous to me), but to your partner it has no nuance or flavor -- they have no associations with that word, nor any grasp of any subtleties of meaning -- in fact they don't grasp the meaning at all. So if you are trying to get something across, it's simply a bad way to do it.
I mean, don't get me wrong -- I don't want to deride big-word-users. If you want to do to because you like it -- that's obviously fine. Also, if someone does happen to have a thing with Brobdingnagian, I guess you might have just made their day a lot better. But at some point, you have to acknowledge that obscure vocabulary is more of a hindrance than a boon to communication.
Children may be precocious and tolerable. I recall the joy of finding new words - grownup words. Most people find it pretentious and condescending in adults. It is poor communication. Want a game of who can think of the most obscure word? Firstly I tried 'widdershins'. Let's exclude Brobdingnagian as an obvious neologism. (Not trolling - really can't see why you think it ain't?)
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.
Nah. I'm proud to say I got everything except Brobdingnagian, which on further investigation is more of a literary reference than a "real" word.
I tried to resist,
but I could not.)
"The problem with defending the purity of the English language is that English is about as pure as a cribhouse whore. We don't just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary."
-- James Nicoll
Dutch - http://crr.ugent.be/programs-data/subtitle-frequencies/subtl...
Chinese - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880003/
There's a few others (Polish, French, etc) but I can't find the links for some reason.
 Zipf’s word frequency law in natural language: http://colala.bcs.rochester.edu/papers/piantadosi2014zipfs.p...
I would say it's like arguing whether Python is more "pure" than Perl. They're both Turing complete, they express very similar concepts but I'd wager most people would concede that Python feels "purer".
EDIT ADD: Zip's Law was not mentioned directly in the blog post but the reply clarified that the API returns a zipf score. However, a word's zipf ranking is dependent on the corpus used. The Wordapi "About" page says most data came from Princeton WordNet but a sibling comment says it came from a subtitles compilation. If the project could clarify the data sources, it would be helpful.
Regarding your update - I'll update the About page.
EDIT: This looks like a case of a common programming antipattern: you don't care about the casing for comparison purposes, so instead of implementing a case-insensitive compare, you downcase the strings and call it a day. But that's inherently a loss of data, and not having that data will eventually come back to bite you.
JACUZZIS FOUND EFFECTIVE IN TREATING PHLEBITIS
"EFFECTIVE" and "IN" are the only two words found in the first 2,000 words sorted by frequency, although "FOUND" is close. So with only 200 words you'd understand:
WNPHMMVF SBHAQ RSSRPGVIR IN GERNGVAT CUYROVGVF
2,000 words would give you:
WNPHMMVF FOUND EFFECTIVE IN GERNGVAT CUYROVGVF
And some grammar knowledge would tell you
WNPHMMVF(N) FOUND EFFECTIVE IN GERNGVAT(V) CUYROVGVF(N)
Which is enough to know that you only really need to look up "TREATING" in the dictionary to understand the gist of the sentence But it'd hardly pass as a fluent understanding...
WNPHMMVF FOUND EFFECTIVE IN TREATING CUYROVGVF
And then some contextual knowledge of what sort of things get treated tells you that CUYROVGVF is a disease or injury, and WNPHMMVF is a medicine or therapy. So knowing 2,000 words and some grammar isn't quite fluent, but it's around the level of a middle-school child who has to ask what lots of nouns are.
"Hmm, Jacuzzis is clearly a noun, so it must be the subject. So Jacuzzis found "effective"... wait, that doesn't make sense. "Effective" is not a company, how does one found "effective"? Oh, it must be the past tense of "find". OK, so these Jacuzzis found... effective? How does one find "effective"? And why was effective hiding in "treating phlebitis"? OK, whatever, maybe I could decipher this if I understand "treating phlebitis"... So it is a kind of disease that is... treating someone (or something)? How could a disease treat anyone? This sentence makes no sense!!"
If you think "Duh, that's ridiculous, nobody thinks like that", then you obviously never met a struggling English learner.
You could probably at least get around.
"(Explained using only the ten hundred words people use the most often)"