My partner doesn't speak Korean anymore. I have the Rosetta Stone for Korean which I tried myself. I can speak FORTRAN, Assembler, C/C++/C#, Java, Perl, Lisp, ADA, Visual Basic, SQL, etc, etc but I needed a tutor in junior high just to pass beginner French ... in a nutshell I didn't do very well with it. But you may have better luck. Tagalog seems a lot easier than Korean to my ears! I don't know what age is appropriate to start them on it if you try, but they should be pretty comfortable with using the computer first.
"I have heard there are troubles of more than one kind. Some come from ahead and some come from behind. But I've bought a big bat. I'm all ready you see. Now my troubles are going to have troubles with me!" - Dr. Seuss