I have no issue calling pho “pho,” yet there are those who would call it “pha” based on the number of people who cannot get tonkotsu and tonkatsu right.
In a number of languages, having one letter off can have a tremendous impact on the meaning of the word (my girlfriend asked how she looked, and I said she was looking very fit/fat).
You say potato, I say po-tot-oh, you say tonKATSU, I say tonKOTSU. Tonkatsu, tonkotsu, tonkatsu, tonkotsu….

Ton-KATSU
No, no, and no, you’re killing my inner happy self. It’s not just a difference of opinion on the pronunciation because it’s actually two different things. “You people,” come on, if it is:
Pork (ton) cutlet, it is “tonkatsu,” chicken (chikin), it is “chikinkatsu,” minced beef/pork (menchi), it is “menchikatsu“.
All three are deep-fried after being dredged in flour, egg, and breaded in “panko” which is Japanese bread crumbs.

Ton-KOTSU
Yes, “they’re,” “they are”, “there,” “their,” might be confusing for some, but at least when you get those wrong, you won’t end up with the wrong order.
“Kotsu“ means roughly “bone stock”.
Spelling Matters
Hopefully, by this point, you might be starting to realize that this isn’t ramen (don’t be asking where’s the noodles), and if it is sinking in, pat yourself on the back although don’t get too cocky because we still need to discuss macaroon and macaron (not the same either).