The history of English Language

 To learn the language, know the history:

Part I

The history of the English language 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, crossed the North Sea from what today is Denmark and northern Germany. At that time the inhabitants of Britain spoke a Celtic language. But most of the Celtic speakers were pushed west and north by the invaders - mainly into what is now Wales, Scotland and Ireland. The Angles came from Englaland and their language was called Englisc - from which the words England and English are derived.

  

Old English (450 - 1100 AD)

The invading Germanic tribes spoke similar languages, which in Britain developed into what we now call Old English. Old English did not sound or look like English today. Native English speakers now would have great difficulty understanding Old English. Nevertheless, about half of the most commonly used words in Modern English have Old English roots. The words be, strong and water, for example, derive from Old English.

Middle English (1100 - 1500)

In 1066 William the Conqueror, the Duke of Normandy (part of modern France), invaded and conquered England. The new conquerors brought with them a kind of French, which became the language of the Royal Court, and the ruling and business classes. For a period there was a kind of linguistic class division, where 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. This language is called Middle English. It was the language of the great poet Chaucer (1340-1400), but it would still be difficult for native English speakers to understand today.

fonte:englishclub.com/english-language-history.htm

This video, although is a little bit old, shows the history of English language and it's very interesting: