You should change the language to English first. I'm not near my Wii right now, but it is in System Settings. Maybe you could get someone who reads Korean to find the option and change it.
If you can load games through a USB drive, then it is already softmodded. It could be hardmodded too. I suggest you follow Softmod ANY Wii in my signature. It will give you Configurable USB Loader, which is the most stable loader available. The setup is great and that guide will update everything for you. You also need to Introduce Yourself.