I want to change the default language

[koinichi]

I'm Korean but because I don't live in Korea, i choose English as my default language when i sign up.
But i want to change it to Korean.
Anyone know how to change it?
I can't find it

[tlfminisd]

I'm Korean but because I don't live in Korea, i choose English as my default language when i sign up.
But i want to change it to Korean.
Anyone know how to change it?
I can't find it

I want another account of my co-worker could be changed to English and found no way either..
I signed up that account when there's no English support yet so I checked Korean....