My father always told me that if you want to do something significant in the world, it is vital to use English almost as a mother tongue. Indeed, he was right in some sense. Even if you continue to live in your native countries, English fluency will enable you to be more successful to change the world.
Why so? It's because in 21st century English-speaking communities are where the world's wisdom and information are accumulated. Most of them won't be translated into your native languages. The information gap between English and the other languages would be widened significantly in 21st century. The main reason is the advancement of information and communication technology. Beforehand, even if one living in India is fluent in English, he or she had no many opportunities to share his idea with those who live in the US. However, now, if you can use English, you can communicate with English speakers (most of them use English as a lingua franca) all over the world. Thus, the knowledge and wisdom of the world's intelligence would be compiled onto English-speaking communities. It is obvious if you compare English wikipedia with Japanese one, see TED, read academic & business magazines, etc.
One may say that auto-translation will be in place shortly, and we may not need to learn English in the future. Granted, perfect computer translators will be available in the future, but given the current pace of technological advancement, I guess it will take at least a decade until auto-translators will be perfect for practical use, and it will take more until auto-interpretors are available. That 10 years could bring us about notable delay in learning new ideas, and it may be difficult to recoup.
Caveat1: needless to say, to be fluent in English is necessary but not sufficient. What I wanted to emphasize is that English fluency is a "prerequisite".
Caveat2: maybe I exaggerated too much. Of course, there will still be the great intellectuals even though they cannot use English. What I wrote is the probability and expected value.
That is why I began my English blog. Probably I will publish my book in English by 2017.