From my experience teaching Zotero, I can confirm that how to change the interface language is a question which occurs ca. in every class 1-2 times. Thus, any more direct way to do that would be appreciated. Maybe, one could also ask the user to confirm/change the interface language during the installation process? That is at least what I see in a lot of other programs in Windows.
FWIW I've had similar questions about easy switching between language interfaces: English/Spanish and English/Vietnamese. I haven't had a good answer to those questions by community college students and university undergrads.
How to change the Zotero interface language from Korean to English (took me some time to figure out):
Select menu 편집 (E) --> 환경 설정 (N) The preferences window will pop up; now select: 고급, and find the pull-down menu 언어, which will allow you to choose your preferred language.
How to change the Zotero interface language from Japanese to English (took me 2 hrs to figure out- but thanks to @catox ):
Select menu (E) --> (N) The preferences window will pop up; now select: the left most tab with tool sign, and find the pull-down menu, which will allow you to choose your preferred language.
To be clear, Zotero uses the system locale by default, so the alternative would just be to make sure your system locale is set to the language you want. (I believe there are a couple different language/region settings that could come into play, depending on the OS, but it's not like Zotero just chooses a language at random.)
Upgrade Storage
Select menu 편집 (E) --> 환경 설정 (N)
The preferences window will pop up; now select: 고급,
and find the pull-down menu 언어, which will allow you to choose your preferred language.
Select menu (E) --> (N)
The preferences window will pop up; now select: the left most tab with tool sign,
and find the pull-down menu, which will allow you to choose your preferred language.