Why do you think so many people are trying to learn and improve their English?

For my mind, people would like improve their English, because it is the main language in the world. If we know English well, we can travel in different country and get new knolage. We can free communicate with different people in the world. In future, I think, English will be the main language. I would add that if we learn English we improve our brain. I think it's very good know English in your life.