Speaking English is the most important skill that a person should learn in the 21st century.
Communication is international. The top three languages that most people speak in the world are Chinese, English and Spanish. The reason Chinese can't be the main language is that compared to English, it's more difficult to speak, read as well as write. English is much easier to learn.
Business is overseas. How do two international companies make a deal? They have a meeting and then they speak English. English is the language that they use to talk with each other.
Speaking English is the most important skill not only in the 21st century but in the earlier century. I'm sure it is still vital in the future.