Apparently I’ve been mispronouncing this for about 45 years. And so has everyone else I’ve heard use it in that time. I’ve never heard it pronounced with four syllables. Too late for me to change now.
Crap, there’s another one. I don’t think I’ve ever heard it spoken, but in my head the “ch” is like church. At least I had the four syllables correct.
OTOH, I guess people in certain parts of New York will get it right immediately.
Ha! I was just about to say that my family was from the Capital District of NY, so I knew how to say this from an early age.
“Skinny atlas,” too. 
That’s another one where the right pronunciation feels weird to me. To me the last bit is doe-(as in a deer, a female deer)-sh.
Ah! The pizza thread just reminded me of one. I don’t think I’ve ever heard this word pronounced, and it seems I always have to look it up to remind myself of the actually pronunciation: geoduck. Every time I come across it, I say “geo-duck.”
IIf you mean with the “ch” pronounced as /k/ as it usually is in the word, that’s very close to how it’s pronounced in German. And when I hear the word in German, I usually think of cows, because that’s how “cows” is sometimes pronounced by a German speaking English with a strong accent.
Duden Online agrees with you (i.e., “ɔ” instead of “o”), but a generic English speaker will probably not try to use a German accent; another random vowel will be substituted, just like with the first vowel “a” 
I usually hear it mispronounced with the “ch” as in “church”.
Ha! I posted on this on the Dope a couple years ago. I lived in Mexico, and people (in Spanish) started taking about cows. Eventually I figured out they were saying “chaos.” That’s how it sounds in proper Spanish (spelled “caos”) — identical except English voices the final sibilant of “cows.”
Somehow, this could be a Far Side cartoon.
I think there’s been a misunderstanding; I should have been more clear, since I now notice some ambiguity in how I phrased it. I meant, a native speaker of German who speaks English, but still has a strong accent.
I also should have acknowledged that the pronunciation of English cows and German Chaos obviously isn’t exactly the same, but they are fairly close, despite the diphthongs being somewhat different, and only English voicing the terminal sibilant.
One word I’ve been pronouncing wrong is Magellan, as in Ferdinand Magellan. It’s got a soft ‘g’.
At least I was pronouncing the names of the Magellanic Clouds correctly, as I’d probably heard Patrick Moore waffle on about them back in the day. (Also a soft ‘g’).
Actually, it seems that both pronunciations are acceptable. And note that it is an Anglicised version of his original name Fernão de Magalhães so really they are both inaccurate.
As far as I can make out, it was pronounced approximately Mag-al-yies with a hard g. According to this IPA reader on the Portugese setting.
My school history teacher taught it with a hard g.
Interesting. So how about the Magellanic Clouds?
I’ve never heard the adjective with a hard g. I think I would say the noun with a hard g and the adjective with a soft g, and I don’t see any problem with that. Proper adjectives often vary from their associated nouns in pronunciation or even spelling.
Christ - Christian
Moscow - Muscovite
The Netherlands - Dutch (!)
The Master Speaks:
That guy is always problematic because of the different forms of his name in different languages, but Wikipedia has both the Portuguese and Spanish versions pronounced with a “ɣ”. The OED has “Magellan” and “Magellanic” with a hard “g”, but it can and does go the other way in other dictionaries.
I always thought the country on the east coast of Africa was pronounced er RIT ria but I just heard it said on tv as erri TRAY a. When I look it up on Wiki it sounds like errtra, with only two syllables.
I’m so confused.
Just heard panache said on the French Open telecast. If offered a wager I would have confidently bet the farm on it being “pa-KNOCK.” Said it that way in my head all my life.
Nope. The announcer said “pa-NOSH.” That is so much worse, sounds like something to do with food. The hard consonant there would do the word a world of good esp. given its meaning , but I am just a mad voice in the wilderness.
[We of course have the Doper ÷panache45. Sorry for saying your handle wrong all these years.]
On Jeopardy!, Ryan pronounced Agincourt differently than I would have. Not sure I’ve ever heard anyone say this word so have read several times.
Actually, it’s closer to pa-nash, with the emphasis on the second syllable.
It’s French, and literally means plume, the type of big white feather worn by D’Artagnon and Cyrano de Bergerac.