Comment 3 for bug 473806

ok, gents. I have the solution as follows. Hope it helps someone:

I'm not sure if you have to enable that 'ibus' option in the language selector. i did so i will add it as a step. Also, of course, make sure you've gone through the process of adding the Korean fonts and all that stuff via the language support window.

1. go to system>admin>language support
2. for keyboard input system choose 'ibus' and close that window.
3. go to system>preferences>IBus Preferences
4. click the 'input method' tab in the middle
5. click the 'select an input method' drop down and search for "korean' by scrolling down
6. you should see romaja, han2 (the ones that don't seem to work) and 'Hangul' with it as well. That's the one that was missing from all my other efforts.
7. select 'Hangul' and then click the 'add' button on the right side of that window.

that's about it. Mine started working after that and I figured out that only the right 'alt' button toggles the language on and off.

I hope this saves someone some grief.