I agree with the above poster. The top priority is to make sure you stay on course for a 2:1 and that you ensure you graduate with that grade. Some employers still won't like your first year results, but you can't do anything about that now so don't focus on it, ensure you graduate with that 2:1. You already know this but don't forget that getting a 2:2 will make it basically impossible to be a barrister (yes, there are exceptions, but let's keep it realistic) and also make it pretty difficult to become a solicitor these days without taking a longer way around. Do not take on anything (you mention leadership roles etc) during your academic year that will impact on the grade that you get. Extra-curriculars can be added to your CV later, you only get one chance at making sure you get that 2:1.
I assume you have no personal connection with Korea and are studying the language for the element of the challenge involved? If it is, say, a family language then no-one will take much notice of it in terms of academic achievement but on the flip side, if you want employers to consider it an asset, then you will need to be fluent and business proficient; they have translators for anything professional that might be required if you are not at that standard. In that sense it's probably no more interesting to most future employers than you being captain of the football or netball team, it shows you have outside interests but not much more. And as above, the top priority is your grades. Be honest with yourself about where the gaps are in your knowledge and work on those, don't hit the easy subjects on the list that you already know over and over, do some extra reading for your course, do practice exams under timed conditions etc to try to improve / stay on course.