Tell me about it! It’s a problem that I still haven’t resolved with 100% consistency.
I’ve gone full circle on a lot of placenames, at least. When was a child, I heard of places like Paris, Rome, Munich, and Seville. As I grew older, traveled more, and became more sophisticated (hah!), and wanted to show my worldliness, the last two became München and Sevilla, even when speaking English. Those were their names, dammit, and I eschewed the English variants. However, I wasn’t so foolish as to use “Paree” for the pronunciation of the first, or “Roma” for the written or spoken name of the second. That would be silly!
I’ve since decided that such usage is inconsistent, and in fact does a disservice to places such as Munich and Seville that have standardized English variants. I now think it’s an honor for a town to be of such importance that people in a foreign country actually have a separate name for it! So, no more München, Sevilla, Firenze, or Venezia for me (except while speaking the local language, of course).
My hardest nut to crack on this is the French city in which I lived for four years, Orléans. As a child reading about Joan of Arc, I would imagine “Or-lee-ans” (with the a being a schwa). Then I learned the French pronunciation (which cannot easily be inserted into an English sentence wihout bringing everything to a halt), and years later the N’Awl’ns pronunciation of “New Orleans”. I still can’t put the name of the place I lived in France into an English sentence and feel happy about it.
Anyway, this is all a diversion from the OP, which is not about “correct” pronunciation that is used inappropriately, but a pronunciation that is flawed from the start:
Hunter Hawk: I’d like a Meh-TAKS-uh, please.
Bartender’s Brain: Hey, that’s a foreign word… I bet it’s not pronounced the way it’s spelled in English… don’t want to sound like a rube… I know that “Mexico” is pronounced “Mehico” … I bet it’s like that…
Bartender*(out loud)*: Certainly Sir, one Metaha coming up!
I hope that the above doesn’t seem too patronizing. It’s something with which I can really identify, and I know that I’ve made similar blunders hundreds of times.
[I grew up pronouncing Cervantes’ classic “Don Kwiksote”, which was correct for the UK at the time. Is it still? I haven’t heard a Brit say it in a while. At least in France it’s spelled *Don Quichotte* and given the corresponding French pronunciation, so there’s no quandary.]