In 2001, linguist Braj Kachru came up with the idea of representing the speakers of English by three concentric circles.
At the center are the native speakers, such as Americans, Canadians, and the English. English is their mother tongue and the language used in daily communication and interaction with others. The number of people in this circle is estimated to be between 320 million and 380 million.
The next largest circle, called the outer circle, is for people for whom English is not their first language, but a language taught and used in their culture for historical or political reasons. Examples include countries like India, the Philippines, and Nigeria. There are estimated to be about 150 to 300 million speakers in this group.
The largest circle by far, the "expanding circle," includes all other English speakers. These speakers learn English as a foreign language and means of international communication. Estimates for this population go as high as 1 billion people.