The history of the English language really started with the arrival of three Germanic tribes who invaded Britain during the 5th century AD. These tribes, the Angles, the Saxons and the Jutes, came from Denmark and northern Germany. With their arrival, most of the Celtic speakers that habitated Britain were pushed into what is now Wales, Scotland and Ireland.
Old English (450-1100 AD)
The invading Germanic tribes spoke similar languages, now called Old English. Old English is extremely present in Modern English.
Middle English (1100-1500)
In 1066 William the Conqueror, the Duke of Normandy and conquered England. The new conquerors brought with them Normand (a French dialect), which became the language of the Royal Court. At this period the lower classes spoke English and the upper classes spoke French. In the 14th century English became dominant in Britain again, but with many French words added (such as ‘castle’, ‘beef’ or ‘royal).
Early Modern English (1500-1800)
Towards the end of Middle English, a sudden and distinct change in pronunciation (the Great Vowel Shift) started, with vowels being pronounced shorter and shorter, due to the influence of many peoples from around the world.
The invention of printing helped to unify and standarise the language. Spelling and grammar became fixed, and the dialect of London, where most publishing houses were, became the standard.
Late Modern English (1800-Present)
The Industrial Revolution and technology created a need for new words. Besides that, the British Empire at its height covered one quarter of the earth’s surface, and the English language adopted foreign words from many countries. This, increased the vocabulary of English language.
Nowadays English, is mainly influenced by the American dialect due to its importance worldwide.
Beside the American and British, we must recognise other varieties such as Australian English, New Zealand English, Canadian English, South African English, Indian English and Caribbean English.
Source : English club