I think the requirement is that ONE of the languages be the person's native language. Because language is so much more than just language, its also about culture. As another commentator pointed out , "cool" can mean so many things, which are in both similar and different at the same time. You need to understand culture to understand these differences.

Yes, English isn't my native tongue but I understand it just as well as a native would, but how many non-native languages can I have such a deep understanding of? I can translate from my native tongue to english and vice versa, but translating between two non-native languages perfectly seems like too difficult a task. Even if I am great at it, its possible that a native speaker of one of the lanugages would be better at it than me