Braj Kachru divides the use of English into three concentric circles.
The inner circle is the traditional base of English and includes countries such as the United Kingdom and Ireland and the anglophone populations of the former British colonies of the United States, Australia, New Zealand, South Africa, Canada, and various islands of the Caribbean, Indian Ocean, and Pacific Ocean.
In the outer circle are those countries where English has official or historical importance ("special significance"). This includes most of the countries of the Commonwealth of Nations (the former British Empire), including populous countries such as India, Pakistan, and Nigeria; and others, such as the Philippines, under the sphere of influence of English-speaking countries. Here English may serve as a useful lingua franca between ethnic and language groups. Higher education, the legislature and judiciary, national commerce, and so on, may all be carried out predominantly in English.
The expanding circle refers to those countries where English has no official role, but is nonetheless important for certain functions, e.g. international business and tourism. By the twenty-first century, the number of non-native English speakers has come to significantly outnumber the number of native speakers by a factor of three, according to the British Council.[2] Darius Degher, a professor at Malmö University in Sweden, uses the term decentered English to describe this shift, along with attendant changes in what is considered to be important to English users and learners.
Research on English as a lingua franca in the sense of "English in the Expanding Circle" is comparatively recent. Linguists who have been active in this field are Jennifer Jenkins, Barbara Seidlhofer, Christiane Meierkord and Joachim Grzega.