That sounds pretty definitive.
As a tangent, the confusion apparently stems from the way Korean is transliterated into English. It reminds me of the oddity of transliteration from Chinese, where “feng shui” is pronounced fung (rhymes with rung or sung)* shway (rhymes with say or day). I’m sure there’s a reason for that, but I suspect it’s a stupid reason. 
*I believe the u is properly pronounced like the u in “put” or the oo in “good,” but I usually hear it as I described.
Judging by comparison with kpop starlet Hyuna (whose name is pronounced basically “Hunna” and sometimes “Hannah” depending on the interviewer), Koreans kinda half-pronounce the y, but Americans don’t really know how to make that particular sound (it’s not hy-un, it’s h-yun, if that makes any sense at all – sort of like the Spanish n-with-a-tilde, except with an h), so “hunday” (i.e., rhymes with the first day of the week) is close enough, as Horatio said.
And, as usual, the Brits just do their own thing.
You could’ve just called it “the Excel,” pretty sure you can’t screw THAT up. Or you could’ve said “the shitbox” because IIRC Korean cars didn’t get good until the mid-'90s at the earliest, just like VW didn’t take off until the late '60s, Honda and Toyota were a joke from the '60s-mid '80s and Chinese cars will probably stop being total deathtraps around ten or 15 years from now.
Bravo on the thread title.
In the US, it likely depends on where you live. In some enclaves, they pronounce Toyota as Tie-oh-tuh, with accents on the the first and second syllables. It’s probably meant to be derogatory or just over-the-top Southern, as in “One a them Tie-o-tuhs.”
Best damn Hyundai commercial ever.
45 seconds long.I’ve always heard pronounced, correctly or not, as Hun-day, rhyming with Sunday, as the OP says.
The Village of Nunda, New York, not far from Rochester, derives from an old Seneca name. It isn’t pronounced the way it looks. it’s pronounced “None-day”, so it ought to rhyme with Hyundai in that case.
I always thought that there ought to be a Nunda Hyundai, if only to confuse the hell out of people trying to pronounce it.
Sadly, although there are Hyundai dealers in the area, there’s none in Nunda, or named after the town. Another opportunity missed.
https://www.youtube.com/watch?v=K0UovyM8Ni0
So, not exactly Hun-day, but that pronunciation is closer than Hi-un-die.
Yeah, it was apparent pretty early on that my sister’s car didn’t excel…at anything. So we all couldn’t bring ourselves to call it that.
I don’t speak a lick or Korean, but i can figure out IPA and Wikipedia’s example is pretty accurate (they don’t say whether the Korean and english differ). I also looked up the Hangul to verify. The last vowel is e as in “bet.” The same vowel occurs in Romance languages, but english speakers usually make it too long into an “ay” sound.
Yeah, that’s what I was getting at, just didn’t think to look up a pronunciation guide.
Hyundai is OK, but how did they come up with “KIA”? I always think of “Killed In Action”!
It’s just another manic Hyundai.
(Bono v. the Bangles: which earworm will win? ;))
It seems obvious to me that it SHOULD be “Hoon Die” (like Moon Pie) but the commercials say “Hun Day” (like Sunday) and that’s good enough for me. If it’s your name, you get to decide how it’s pronounced.
What drives me up a wall is I know someone who keeps saying “Hahn Da” (like Gone Tab), which sounds way too much like Honda for my taste. There are days when I wonder if he even knows that Hyundai and Honda are two different companies.
Hyundai, Hyundai, so good to me.
Hyundai mornin’, it was all I hoped it would be.
Mawzduh? Who would say that? 
BTW in the UK I’m sure the more recent ads say “Hyun-day”. I remember thinking it sounded odd but was probably more accurate, as I remember them being called High-un-dies in the 1980s.
How do Americans say Nissan then? Is there even another way? Rhymes with “Kiss and” (tell).
Now I’m really confused. “Hahn Da” sounds nothing like “Gone Tab”. Surely you mean Honn, not Hahn? Honn rhymes with Gone. Hahn rhymes with Barn or Calm.
Well, I guess maybe more of a “Mahhhzduh.” The important part is the soft A’s, unlike the hard A’s the rest of the English-speaking world uses to pronounce it.
Although Mazda is kind of an interesting case in that the pronunciation of it in the home market is completely different because it’s not a Japanese word and (AIUI) Japanese has funky pronunciation rules for foreign words. So there’s not really a “definitive” pronunciation, although I guess you could go back to the original Persian.
“Nee-San”
The Japanese name of the company is Matsuda, which is very much Japanese - it’s the name of the company’s founder. The English name of the company is derived from this, as well as being a reference to the Zoroastrian god Ahura Mazda.
This is how the Korean woman in Greg Charles’s link says it.
You pronounce it like one of these? We say ‘NEE-sahn’.
As for Mazda, the commercials I see from a few miles north of me pronounce it ‘MAZZ-duh’. We pronounce it ‘MAHZ-duh’.
In any case, I think my original question has been answered. Here’s another one:
What is the proper pronunciation of Hilux? My dad had one, way before they became the Tacoma. We pronounced it ‘high-lux’, as in ‘high luxury’. But I’m pretty sure I’ve heard it pronounced ‘hee-lux’ on Top Gear. This is the pronunciation suggested by the spelling; but ‘high-lux’ makes more sense for a car (even if that car is a truck).
IANA Japanese speaker, but my understanding is that the pronunciation of the Persian word “Mazda” in Japanese (given the funky pronounciation rules) is something very close to to Matsuda. The name of the company versus the name of the car brand is something of a pun.