English is a West Germanic language that originated from the Anglo-Frisian and Old Saxon dialects brought to Britain by Germanic settlers from various parts of what is now northwestGermany, Denmark and the Netherlands. Up to that point, in Roman Britain the native population is assumed to have spoken the Celtic language Brythonic alongside the acrolectalinfluence of Latin, from the 400-year Roman occupation.

One of these incoming Germanic tribes was the Angles, whom Bede believed to have relocated entirely to Britain. The names 'England' (from Engla land "Land of the Angles") and English (Old English Englisc) are derived from the name of this tribe—but Saxons, Jutes and a range of Germanic peoples from the coasts of Frisia, Lower Saxony, Jutland and Southern Sweden also moved to Britain in this era.

Initially, Old English was a diverse group of dialects, reflecting the varied origins of the Anglo-Saxon kingdoms of Great Britain but one of these dialects, Late West Saxon, eventually came to dominate, and it is in this that the poem Beowulf is written.

Old English was later transformed by two waves of invasion. The first was by speakers of the North Germanic language branch when Halfdan Ragnarsson and Ivar the Boneless started the conquering and colonisation of northern parts of the British Isles in the 8th and 9th centuries (see Danelaw). The second was by speakers of the Romance language Old Norman in the 11th century with the Norman conquest of England. Norman developed into Anglo-Norman, and then Anglo-French - and introduced a layer of words especially via the courts and government. As well as extending the lexicon with Scandinavian and Norman words these two events also simplified the grammar and transformed English into a borrowing language—more than normally open to accept new words from other languages.

The linguistic shifts in English following the Norman invasion produced what is now referred to as Middle English, with Geoffrey Chaucer's The Canterbury Tales being the best known work.

Throughout all this period Latin in some form was the lingua franca of European intellectual life, first the Medieval Latin of the Christian Church, but later the humanist Renaissance Latin, and those that wrote or copied texts in Latin commonly coined new terms from Latin to refer to things or concepts for which there was no existing native English word.

Modern English, which includes the works of William Shakespeare and the King James Bible, is generally dated from about 1550, and when the United Kingdom became a colonial power, English served as the lingua franca of the colonies of the British Empire. In the post-colonial period, some of the newly created nations which had multiple indigenous languagesopted to continue using English as the lingua franca to avoid the political difficulties inherent in promoting any one indigenous language above the others. As a result of the growth of the British Empire, English was adopted in North America, India, Africa, Australia and many other regions, a trend extended with the emergence of the United States as a superpower in the mid-20th century.