Nobody knows how many different languages there are in the world. The most widely used language is English. It's used by business people, airline pilots all over the world. It's also the first language of sports and science. So it's very important for us to learn English.
English is most widely spoken in the world, while Chinese has the largest number of speakers. There are not only over one billion people living in China, but also many Chinese people living outside of China. You can find large or small groups of Chinese people living in almost every country in the world.
There are some other important languages in the world, too. Chinese is of course very important, especially in Asia. Arbic is widely spoken in many parts of Asia and Africa. Russian is spoken both in Europe and Asia. French is widely understand, not only in Europe, but also in parts of Canada, Africa and Asia, Spanish has a growing number of speakers all over the world, especially in Central and South Africa.
What language do people speak in the United Nations? There are so many different languages in the world, but they decide to use only six of them. There are Arabic, Chinese, English, French, Russian, and Spanish. Everything spoken or written in one language is translated into the other five.