I think it's always best to learn Korean, it significantly increases your chances in a highly competitive company, and will help you communicate effectively with the staff and other auditionees there!

I understand why it's helpful, but you're waste your time. Your rapping, dancing, or singing skills are more important, and you can learn once you're accepted as a trainee.

You NEED to learn Korean - I'll put some tips and methods in the comments to help everyone out ૮˶• ﻌ •˶ა