Harrison Holt of The Generalist Papers offered a very brief but thorough animated explanation of the history of the English language. Holt first travels back to its very roots, noting how some modern languages originated from the same source.
This is the Indo-European language family. It stretches from the north of India all the way to Western Europe. Almost half of the global population speaks an Indo-European language and that includes you and me. English is an Indo-European language, specifically part of the Germanic branch of the family along with languages like German, Dutch, and Swedish.
The history takes Holt back to the age of the Anglo-Saxons where Old English was spoken. It then combined with Danish and Norman French to become Middle English. When the Great Vowel Shift took place in the 15th century, modern English was developed. This particular form of English continued to evolve up through present day. And it will continue to do so.
English today is still evolving as much as it ever was with new words being added to dictionaries every year, as well as many old words falling out of use. English grammar is also changing and it will continue to change. So much so that in a few hundred years our language will sound just as foreign to future English speakers as Chaucer does to us.