There certainly is a name for those people, and Thomathy has mentioned them. They are called "prescriptivists", and their self-righteousness is fairly well known. I believe the formal definition is someone who thinks that there is only one side to a coin. 

A prescriptivist would be more likely to hit your uncle over the head with a cue stick for fucking around with the "correct" pronunciation of the word. In other words, you are the prescriptivist for taking him to task over the issue.

Where I come from a person who deliberately mispronounces specific words in the stupid hope that it infers a superior knowledge (one not in evidence based on anything else they utter) is called a "pretentious twat". Even the prescriptivists agree on that one!

Well, it need not be prescriptive. My father was a fan of mispronouncing words but he did so as a parody of people who are too full of themselves. I have picked up the habit from him.

For example, if I was in Paris and I wanted to buy some minor trinket, I would be fine with going to a boutique. However, I am not in France so knick-knacks are purchased at a bow-tee-kew. This is America and English is spoken here. You can call it a shop or a store and it remains the place where minor bits of crap can be purchased.

If I further want to parody poor speaking, I might say that I am “Sick-n-tired” of people who think that there are ways to use language to be cute or clever. Guess what? You are not making a positive impression on me by doing that and I will not buy any product that replaces the conjunction “and” with the meme -n-.

Same thing.

That may account for the mispronounciation.

That is prescriptive behaviour. You cannot call it parody unless you believe the object of the parody has broken a linguistic rule - in your examples having employed a "foreign" word to replace a more "indigenous" word (for reasons of being "posh" ), or having used an extreme abbreviation (the letter 'n') to signify the word "and" (for reasons of thinking it's "cute" to mimic slurred pronunciation in text). A descriptivist however would acknowledge that both are comprehensible and add them to the dictionary on that basis without question.

Once you insist there is a correct rule of any description you are being prescriptive. If on the other hand you believe that rules, such as they are, change constantly as they are based completely on current usage then you are the opposite to prescriptive and are being descriptive.

The confusion on this thread seems to have arisen from the assigning of a negative character to prescriptivism and saying that anyone so described is being "self-righteous". It is not negative. It is an essential approach when teaching language. Grammatical rules, for example, cannot be formulated on a descriptive basis in a manner useful to teaching. On the other hand an excessively prescriptive attitude to language-use denies recognition of its evolution in the vernacular, a policy which rapidly leaves the prescriptivist out-of-touch with his own language.

Hm. Usually I only hear the term "prescriptivist" used when talking about rules of grammar and usage for standard written English. (i.e. the people who get their panties in a twist when you commit the "sin" of double negation or ending a sentence with a preposition).

I guess it's possible to be prescriptivist about pronunciations, too. For example, in the word "vehicle", some people pronounce the H and some people don't. In the word "garage", some people pronounce the second syllable with a soft J, making it very similar in sound to the word "mirage", whereas others give it a harder, affricate pronunciation along the lines of "gerr-odge".

You could be prescriptive and say that one pronunciation was the "correct" one, but you'd just end up looking like an asshole. Language is never technically "correct" or "incorrect". It's more along the lines of being "fashionable" or "unfashionable".

But I would argue that there does come a point where you can no longer cry prescriptivist. For example, if I'm the only person on earth who pronounces the word "pineapple" as "peen - YOP - lay", then I can't call you a prescriptivist for correcting me. You can't just make up a new pronunciation and claim that you're your own dialect.

In other words, there ARE prescriptivists out there. But there are also people who just do whatever the fuck they want out there.

My advice: if you can find a group of people out there who regularly say "akyoostick", then he's off the hook. Otherwise, he's probably just hypercorrecting or trying to impress someone.

(If it makes you feel any better, my dad often pronounces it "agoosta" as in, "Did you buy some strings for your agoosta?" In his defense, he knows he's not pronouncing it right every time he says it, but he just can't seem to make the correction.)

What's really annoying is when they do it after you have just imparted something you really meant them to understand or which articulates a thought crucial to you.

As in:

"My wife has just died and they don't know what she died of."

"You mean - they don't know OF WHAT she died."

"Fuck off, creep."

Actually the OP's father has wandered into a very long established prescriptivist minefield in the choice of the word whose pronunciation he has decided to unilaterally mangle. "Acoustic" is one of those words which defies one to remember how it is spelt. So strong is the urge to place an extra "C" within it that it has become something of a protected species in the eyes of many prescriptivistically inclined and therefore worthy of vociferous defending in their eyes. This is confirmed readily by a Google search which returns 76,400,000 hits for the word with two "C"'s as opposed to a mere 75,300,000 for its correct spelling.

But it's been a long campaign, and one that will apparently be fought to the death of prescriptivism since it seems it has been fought right from its birth. The word 'acoustic' was first applied in a scientific sense to the quality of sound in 1683 by Sir William Petty who published a treatise on the subject for the Royal Philosophical Society, the same body which also led the vanguard in the original campaign for standardised spelling in English. In Petty's treatise he used the word 173 times, of which he (or the society's publisher) managed to insert an extra "C" 53 times.

History however does not record if his accompanying lecture to his fellow Philosophers was peppered with cue-sticks or not.

Thankfully, though, the word was used long before that by ancient Greeks, who would not use a "cue" sound to say "ἀκουστικός" (akoustikos). The "ou" in there is pronounced "oo" by most scholars of Greek, while the rest pronounce it slightly closer to "ow".

So at best, your friend would be trying a slightly controversial "a-cow-stick" pronunciation. Otherwise, for 2,000 years, the pronunciation has remained "a-koo-stick". Trying to sound British is smashing, really, just spiffy. But let's not get carried away like they did in the middle of the 20th century with the mid-Atlantic accent. Unless you're Cary Grant, that shit's just made up.