The use of the English language in current and former countries of the Commonwealth was largely inherited from British colonisation, with some exceptions. English forms part of the Commonwealth's common culture and serves as the medium of inter-Commonwealth relations.

Commonwealth English refers to English as practised in the Commonwealth; the term is most often interchangeable with British English, but is also used to distinguish between British English and that in the rest of the Commonwealth. English in the Commonwealth is diverse, and many regions have developed their own local varieties of the language. The official status of English varies; in Bangladesh, it lacks any but is widely used, and likewise in Cyprus, it is not official but is used as the lingua franca.

Written English in current and former Commonwealth countries generally favours British English spelling as opposed to that of American English, with some exceptions, particularly in Canada, where there are strong influences from neighbouring American English.

Southern Hemisphere native varieties of English began to develop during the 18th century, with the colonisation of Australasia and South Africa. Australian English and New Zealand English are closely related to each other and share some similarities with South African English. Nonetheless, South African English has unique influences from indigenous African languages, and Dutch influences inherited alongside the evolution of Afrikaans, while New Zealand English has a lot of influences from the Māori language.

Canadian English contains elements of British English and American English, as well as many Canadianisms and some French influences. It is the product of several waves of immigration and settlement, from Britain, Ireland, France, the United States, and around the world, over a period of more than two centuries.

In many Commonwealth countries, there exists a relatively small native Anglophone minority amongst a larger population who speak English as a second language; Anglo-Indians speak English as their mother tongue, but it is not the first language of most Indians.

In addition to South Africa, a number of Commonwealth countries in Africa have native varieties of English. A community of native English speakers exists in Zimbabwe; the country's dialect bears features of British English, South African English and other Southern Hemisphere varieties of Commonwealth English. Also in Southern Africa and with historical influence from South Africa, Namibia and Botswana have their own dialects, with smaller native English-speaking populations. The same is true of Kenya and Uganda in East Africa.

Caribbean English is drawn from British English and West African languages. It is influenced by constant contact with English-based Creoles. There is considerable influence from Hindustani and other South Asian languages in countries with language Indian populations, including Trinidad and Tobago, and Guyana. Jamaican English and Barbadian English bear influences of Irish English.