The English language is important to people in many parts of the world because it is their native language. But I doubt that's what you mean.
The English language is important in the world today because of the dominant position of the United States in an increasingly globalized world. Because it is important for many countries to do business with the United States, it is helpful for the people of those countries to learn English.
Since this has been true for most of the period since World War II, many people around the world have learned the language. Since they have, it has become a way that, for example, a French person may speak to a Japanese. English has become the lingua franca of international business.
I don't know if that's what you mean, though. Please let us know.