Have you heard of a small rainy group of islands at the top of Europe? Of course, everyone has heard of Britain, England, the United Kingdom etc. What is it that makes these islands so famous? The English language.
English really is a mongrel language and its history is deeply tied to the history of Britain. The history of English really begins fourth century AD after the Romans withdrew. Although the Romans and Celts left some remnants of their languages behind it hasn't left a deep impression on English. As for the Celts, they were largely pushed into mountainous and remote areas of the British Isles such as Wales, Cornwall and Scotland. England meanwhile was conquered by Germanic tribes (principally the Jutes, Angles and Saxons). Did you know that 'Tuesday', 'Wednesday', 'Thursday' and 'Saturday' are named after Anglo-Saxon gods?
In 591 AD Christianity was introduced to Britain and this led to the re-introduction of Latin words such as 'bishop' and 'martyr'. Later in 800 B.C, the Vikings arrived and actually settled in Northern England. They introduced lots of words related to war i.e. skull, knife and die but also place names (in the North of England many of the towns and villages ending in 'by' have Viking routes.
1066 or 'The Battle of Hastings'. This was the last successful foreign conquest of Britain. In 1066 a group known as the Normans conquered Britain. The Normans or ' North Men' were themselves descended from Vikings who settled in the North of France in 'Normandy'. With the Norman conquest, the Anglo-Saxon elite was largely replaced by a Norman elite and the language of the state became French. All official business was conducted in French. Words such as 'judge', 'jury' and 'justice' entered the English language. The peasants at this time still spoke Anglo-Saxon dialects. Therefore more sophisticated words usually have Latin or French roots and more common vocabulary has Germanic roots. Examples of this include 'gathering' vs 'assembly' or 'pig' vs 'pork'.
Eventually, after several centuries the Norman elite was long removed from its French origins and adopted the hybrid of French and Anglo-Saxon English that had developed as the language of the court. King Henry IV was the first king to take his oath in English.
Shakespeare had a profound effect on the English language adding about 2000 words to the language. He coined words such as 'alligator','eyeball' and 'anchovy'. He also coined lots of catchphrases such as 'flesh and blood' and 'house and home'.
In 1611 the Bible was translated from Latin into English and introduced lots of new phrases such as 'labour of love', 'from strength to strength' and 'to go the extra mile'. With the enlightenment period in the 17th century, lots of new scientific vocabulary was invented such as 'physicist', 'electricity' and 'gravity'.
The age of the British Empire started in 1583 and lasted till approximately 1914. At its height the British Empire covered nearly a quarter of the world. English vocabulary expanded at lightning speed throughout this time accumulating words from every corner of the globe. For example words such as 'barbecue' and 'canoe' come from the Caribbean while 'dinghy' comes from India.
American English - or somewhere in that ballpark. When the British arrived in America they took words from the natives such as 'racoon' and 'moose'. Later new waves of immigrants such as the Dutch and Italians arrived and added words like 'coleslaw' and 'spaghetti' to the English language. After the Second World War, the United States became the principal power in the world and spread new words and phrases like 'blue chip', 'blue collar', 'white collar', 'freeway' and 'bottom line around the world.
These days there are actually more non-native speakers of English than native English speakers. This means that most conversations actually take place between non-native speakers (i.e. a Chinese Engineer calling a French client). This is known as International English or English as a Lingua Franca. Also with the advent of technology, new words are constantly being invented such as 'memes' and 'selfies'. English has transformed and transformed the world. What English will be like in 100 years from now is impossible to say.