[Vote to reopen if you think the spoken language is worth exploring, and I think ELU includes the word 'usage']
Should you pronounce a word according to the region in which you are, as best you can?
For example, if someone is from Nevada, where everyone would pronounce 'advertisement' similar to adver tise ment, would it be considered pretentious if they pronounced it ad vert isement?
The french pastry has a an obvious longstanding pronunciation in American English as 'kruh-sahnt' (croissant). If an American then says 'krwah-sahn', particularly to another American, it seems out of place and disruptive to the conversation.
Another example is when a non-spanish speaker (I'm looking at you NPR), pronounces latin surnames and countries with a (sometimes heavy) spanish enunciation. Rodriguez can have a heavy spanish pronunciation, but then they pronounce Mexico in the American pronunciation, i.e. not 'Me-he-co'. It's inconsistent and annoying.
Is pronunciation relevant?
Should pronunciation, and even spelling (color vs. colour) be more conscientious of the speaker/listener relationship, and is not doing so, considered rude or pretentious?
When you learn a word, do you not ask "how does it sound?"