First off, I'm a linguistic student studying English(US & UK version), Japanese(major in Kanto-ben, minor in Kansai-ben & Aichi-ben), Chinese(major in Mandarin, minor in conversational Cantonese), Deutsch(Standard), French(Minor take), Malay(Malaysian region), and Spanish(Minor in conversational).

Born as a mongrel that of Japanese and Chinese heritage. Brought up and educate in an International British Boarding School, and have lived in the English environment for more than 11 years. Have had a rich experience travelling around the globe in enriching and brushing up my languages to a certain extent level.

Well, when you speak bout which language is the toughest to master, I'd tell you guys, frankly, from my studies, experiences, environments I've dwelt in, and all -- Japanese is one of the toughest to master, followed by Chinese; as the pronunciation has to be very accurate and precise at all times, French taking the third place due to the difficulties one encounter always in pronunciation, lastly, English, though it's international, but as long as it's spoken and written generally, and even broken, English speakers tend to and/or will often understand what the shit you're trying to express to them, for real. If you're ever skeptical, why not drag some asian who's bad at english to speak english with you today, and see what I mean for yourself?

Cheers.