[direwolf20]

If my concern is % of GDP I'd rather learn Mandarin.

[yetihehe]

I tried to learn Mandarin and it's really hard! That's coming from someone who is able to say Grzegorz Brzęczyszczykiewicz without a problem.

[ryoshoe]

I feel the perceived difficulty varies from person to person. Personally I found Mandarin much easier to pick up than German or Spanish, since you don't have to worry about conjugation.