Wow, so many replies. I am going to ignore the ones that are a direct reply to someone else, otherwise I'll still be writing this reply monday morning.
I get this, but it's really not an opinion thing

It's just how the language works. Some things are just facts, no matter what people think of them, haha
Even when things just work the way they work, you can still have an opinion about them.

Like the sky is grass is gree and the sky is blue. You can think it is pretty or you can think it would look better is the sky was red and grass was yellow.
I think your original post is a very good question! Maybe I'm inferring or projecting too much meaning into it, but I thought it came from a place of "hey native speakers: what
sounds good to you?"
Why do I think it's important? Because I've played plenty of RPGMaker (and indie) games where I could
tell that English was not their first language. And this is even when their grammar is perfect. This is because they go by the book but they have not spent the time to pick up all the weird, unexplained nuances this nonsense language has.
I certainly would hate to try and write something that is meant to be this beautiful thing only for my audience to be distracted and say, "Why did he say it like that?" because of some strange, built-in knowledge only a native-speaker would pick up on.
And, in case I wasn't making this clear, speaking with perfect grammar sounds awkward. It basically makes your characters into robots.
This is literally a trope the sci-fi genre uses all the time.
True. I like to use easy English and avoid words that are hard to spell and replace them in my mind with easier alternatives. I don't use many hard words but the ones I use, I want those to be correct. That way I seem smarter than those who use expensive words wrong.
Learn English. 1 FREE English lesson added every single day. Grammar, vocabulary, listening & reading
www.ecenglish.com
I learned something, letters which are spoken like a vowel also use an. Always thought "a npc" but you are right it is "an npc".
Yeah, I though that too. I always say "an NPC", but I used to write "a NPC". Funny thing, right?
many people use "NPC" to denote and speak the whole of "non-playable character", in which case, *a* "non-playable character" is correct, when spoken.
B U T !
given that we're on a written media, and the use of "NPC" (literal) should be meant as shorthand for "non-playable character" both explicit and implicit by context, having been the relationship between 'NPC' and 'non-playable character' established beforehand (such being the point of using the acronym!), any occurrences of 'NPC' should be read as the acronym itself: N, P, C.... and as such, be lead by 'an', as per English grammar rules.
source?
10 years of Spanish-speaking school side-teaching the fundamentals of English grammar.
If I understand you right, when you read "NPC", you say "non-playing character"? I don't think many people do that, though.
Would be funny if you were an FBI agent: "Freeze! Federal Bureau of Investigation!" Half the netflix series would suddenly be twice as long.
I forgot about the spoken vowel and everytime i typed "an NPC" in the Forums, i corrected it to
"a NPC". Atleast dozens of times XD.
Thanks for the Language lesson.
Same story.
Based on what I've learned in English class. N's pronunciation starts with a vowel, so "an" is used.
My last English class was more than half my life ago.

Damn I'm old... :'(
I'm so baffled as to how this thread is still going


It's a question with a definitive answer which has been given. What more is there to talk about?
Plenty!

I told you it was a matter of opinion, even though no-one is denying that "an" is correct.
your answer is your personal subjectivity iron,
we must come to a democratic vote of majority,
to finally solve these problem!
Hmmm. I started the vote already, so who knows.

But even if every American would vote, I can't make it official. Trump wouldn't listen to me cause I'm European and not a multi miljonair. Joe Biden doesn't listen to me because... Well, probably the same reason. I doubt either of them even believes my country is real and that it is not the fantasy land of Peter Pan and Captain Hook.
(Oh they probably do now... Since at this axact moment, we're busy kicking USA out of the world championship soccer. 2-0!! 2-0!!)