@Celedith no shade meant! I personally think its fun to learn words and honorifics in various languages as I read stories (I only know things like gege, jiejie, shifu, unnie, noona, nim etc from reading chinese and korean manhua/manhwa). Even japanese terms could only become so widespread by people using them in translations after all.
I think its a valid concern to think about people who aren’t aware of chinese terms, maybe you could put a little tl note saying something like “er-jie is like the chinese equivalent of onee-san for women around the same age” as a way to help people who are unfamiliar?
Thanks again for picking this up!