You can change your default locale with the following procedure.
Choose the language button on the dtlogin window.
Select the C, ko, or ko.UTF-8, ko_KR.UTF-8 or ko_KR.EUC locale.
Your new locale is in effect.
You can use aliases to change a terminal-emulation window between the Korean locales and ASCII/English locale from time to time without typing long command lines or editing your .dtlogin file and running source every time.
Put aliases like the following in your .profile file.
alias kor_EUC "export LANG=ko; /bin/stty cs8 -istrip defeucw" alias kor_UTF "export LANG=ko.UTF-8; /bin/stty cs8 -istrip \defeucw" alias asc "export LANG=C; /bin/stty cs7 istrip defeucw" |