I'm already fluent in Mandarin and English and have some Japanese, Taiwanese, and Cantonese. If I had extra time specifically for language learning, I'd like t

I'm already fluent in Mandarin and English and have some Japanese, Taiwanese, and Cantonese. If I had extra time specifically for language learning, I'd like to have the Japanese become fluent and pick up some Spanish and Russian. Japanese because of its enormous economic and cultural clout, Russian, because a lot of Russians live in this part of the world, and Spanish because it's the second most common first language on the planet after Mandarin, which I already speak.