To be fair English is already the worlds' language, it's uses extend from political events, business meetings, video-games, movies, music and so on. English is the lingua franca for most worldwide events where participants do not share the same native language. Why this happened? Well, first the British empire was huge and present everywhere, this helped the language spread across the 5 continents as a language used mostly for trading and bargaining . More recently with the rise of the USA as a World Superpower almost every piece of culture or product or service is presented in English as the original language, which makes the language very valuable to learn. That's why it is taught in school on most of the world's developed countries.