The thing is, namjoon is not just speaks in english, he gives speech in english in a way that not all of us (native or bilingual) can do it too. He started learned the language for daily conversation but now he is giving speech in english, in public, in front of a lot of people. Even natives may have the difficulties giving speech in their own language. So appreciate namjoon more. He is not only giving a speech, it was always been a great speech which prepared carefully, and conveyed earnestly so the messages he and the boys want to say to us delivered beautifully. Like jin said, appreciate namjoon english more, he always try his best to represent bangtan as their leader.