beside chinese, the 4 ones as below

1. English-- widely used worldwide

2.Japanese--comic fan

3.cantonese--influence by TVB TV series

4.spanish or French----have not decided yet, a EUROPEAN language , I want to travel there

korean - similar reasons to japanese, but it's definitely a unique culture in its own right. arguably the most thriving pop culture in asia (don't really wanna get into a debate about that, i like jpop and jdrama too, damn). also really far ahead in the high tech dept, building robots and shit, top-notch consumer electronics, etc., right along with jp and certain western countries.
thai - muay thai: most brutal martial art in the world my opinion, thai food: not much that needs to be said, the society has been centered around food for so long so it's gotta be good, fresh, filling, strong yet subtle, and also healthy, all at the same time, so many complex flavors blended together perfectly. also clothes and food and rent is really cheap there.

then let's throw in french and swedish to get some euro in there. yeeuh

chinese - biggest population in asia/ ..the world, so much of asian heritage originated from china, also kung fu is cool
japanese - one of the most sophisticated and refined societies around, from both a traditional and a modern standpoint, so many of the aspects of the culture appeal to me personally

danish, greek, arabic and thai

1,chinese....china have most people in the world~! If You had the language ,you can communicate 20 percent of the world.
2.English....
3.japanese...
4....................