A common ground of language needed to be established so people in areas like the workforce, would be able to understand one another. And English is the most commonly spoken language all throughout the world. English isn't the official language of every country but it's the most popular official language when compared to others such as Spanish or French. Therefore, English became a global language because it was easy to learn, and something that everyone would be able to understand regardless of what their primary language is.
English may not be spoken language in the worlds, but it is an official language in a large number of countries. It also very important for whom works in global workforce because English is the language of business in world, so it had become necessary for people to speak English.
