Whenever I tell people how many languages I am learning, people often ask me "Well then, what language is harder?" and in the end I am never really able to give them a straight answer.
If we were to look at statistics and fact, there are numerous reports and studies that have argued one way or another. Check out this article HERE or even on Wikipedia.
Personally, although I could understand why these languages have been ordered like this, I still think they can't be 100% trusted. People are different and therefore, they learn and understand things differently, I might find learning vocabulary really easy but find grammar rules difficult but then for another person it could be completely different.
I did find it was easier to learn german than french. In fact, I have studied french for a year longer than german but my french and german proficiency are roughly the same. Therefore, another factor to consider, could be whether this is your first foreign language. Although, I can understand why korean is considered hard, at the moment, I find basic korean quite easy as although korean grammar is different than english grammar, I am used to the 'language of languages' so things like 'past tense' 'cases' 'suffix' 'qualifier', I'm used to learning about the building blocks of languages so when I learn a new language, it's just a case of modifying the rules. (I'm sorry if I'm confusing anyone. ^^) I hear people who speak 6 or 8 languages saying "it does get... easier!"
What about you, what do you think is the hardest language in the world?