The only way to change the language is by changing the values of the settings.txt. Game update should not do this. I am almost possible that this is a failed region change.
Try to update from a game iso with 3.4 update
You need any game iso on your pc
A burner with some good dvd media
Wii Update Manager
Open your game iso in Wii Update Manager. Replace the update with 3.4u.
Then use Wii Autoboot Creator.zip to set the iso to autoboot.
Try to boot the game using savemiifrii, cross your fingers.
The trouble is, a korean wii with all of its setting set to usa should still boot. So it is possible that your settings are only half changed and could cause trouble booting games. Best of luck.