An application that uses the htt input method server to receive Korean characters must find htt running before it can receive such input. So if your default locale is the C locale (which does not require htt) and you then change from C to another locale in a single Terminal, for example, you must start htt with a command line like the following:
system% htt &
With the locale set to ko or ko.UTF-8, htt is started automatically when the Korean windowing environment starts up. In CDE, htt is started from a script, /usr/dt/config/Xsession.d/0020.dtims. This script is executed by Xsession, which runs at every initialization stage upon a user's login from dtlogin. This script ensures that htt is started before other applications in CDE.