For me learning foreign languages is the best way to see the world :)

Selman in Europe, the first is Russian, the second is German. if you wanna say in EU, the first is German

Selman the most spoken language is Chinese, not English. English could be the most studied language in the world. 

To have oportunity  earning more money))) if to be honest and also to learn new cultures. 

I learn English, because I need it in my job. The second reason is wide array of resources in English.