“par-meh-ZAHN”
Johanna - You spoke French! – John Astin as Gomez Addams. 
Interestingly, dictionary.com gives various accent patterns and different vowels, but no “zh” variation:
FWIW, Merriam-Webster has it
Courtesan
I thought so too, but I couldn’t find a dictionary entry that actually corroborated this. I always pronounced it like parmesan, but the dictionaries all had the final syllable “san” rhyming with “fan”…
Here we go again. 
As I learned on the Dope years ago (from @hibernicus), the “a” vowel in Romance languages doesn’t exist in English. It’s halfway between the English sound in “pan”
(ae) and the English* sound in “hot” (ah).
The standard British approximation is the “ae” sound. The standard American approximation is the “ah” sound. Neither is more right — nor more wrong — than the other.
*Well, the common American sound in “hot,” anyway, especially in California (but not just there). That is, without any lip rounding.
Yeah that’s one I never heard. Parmesan with a “zh,” yes. Never heard it in “courtesan,” but it’s not like that word comes up a lot.
“Please pass the parmesanclod”.
Sometimes we pretentious English speakers just like to zhuzh things up a little bit.
I’m afraid this is just wrong. For one thing, when you say English, you seem to mean American English. Both pronunciations of “a” exist in English as it is spoken in England.
The problem for American English seems to be the lack of a proper “o” sound (because, as you say, of not rounding the lips).
I suspect that what’s going on with the American pronunciation of Parmesan is that there’s apparently a trend to performatively attempt to pronounce a random selection of loan words in something approaching their original pronunciation.
The issues are that this is not how English conventionally treats loan words, Parmesan is not an Italian word, and if it were, Italians wouldn’t pronounce it like that.
And sometimes we keep things cazh.
We pronounce it “Romano”.
I don’t think you guys are understanding the question. None of those words are pronounced with a “zh” sound as in Parmesan. Like the word zhuzh.
Both pronunciations of “a” exist in American English as well.
I believe
refers only to the “a” in parmesan. The British pronunciation uses a different vowel than the American pronunciation.
I think this is one of those situations where it’s hard to convey pronunciation in text without using IPA proper (or even if you do, most people wouldn’t know how to read it, myself included… it looks like a weird mix of ancient foreign alphabets and math notation).
I knew what the OP meant, but only because I’d heard “parmesan” spoken the American way before. If I just saw “zhan” written out in a text, I’d have assumed it’s pronounced “zan”, with a silent “h”, rather than a mix of “Sean” and “John”.
And zhuzh looks like “zoo, uh?” to me.
I believe it’s pronounced par-mee-zee-an by everyone in the universe
Parmesan from the Parisians, duh. Makes total sense to me! 
We’re arguing over the French pronunciation of “Jean” (zhan) or the American pronunciation of the first syllable of Xanadu (zan), right? I’ve only heard the former for the last syllable of Parmesan.
I think so. But many Americans wouldn’t know the French pronunciation of “Jean” either, I think? At least judging by the number of times I’ve heard “John-Clod Van Damn”.
I think it’s the sound in the middle of measure or vision or at the end of lavage.