How old is English?
 Wales came under English dominance in the Middle Ages (1277) and yet some 750 years later pockets of
Welsh persist. Such pockets are typical for where new languages were introduced. They can be found all over the world.
 William commissioned the writing of Domesday Book. This book was the record of the great survey of England completed in 1086. The survey was similar to a census by a government of today. It mentions place names, river names and names of local landowners. Domesday Book contains no place-names of Welsh origin.
 There is one exception: after 1066 AD, French remained for a very long time the language of the English
aristocracy. Richard 'Lionheart' was called in reality 'Richard Coeur de Lion' and spoke not a word of this commoners'
language, called English.
 Sam Newton, "The Origins of Beowulf"
 In the Middle Ages the city of Bruges felt a strong French language pressure coming from Paris and
London. Luckily, the city was as rich as both taken together, so Flemish had no problem of maintaining itself.
Chaucer can still be read today despite the fact that he wrote 700 years ago. His words are even more understandable for someone who knows Dutch. In fact, the spoken language has changed relatively little over the last 800 years. The very same can be said about most other local tongues in Europe. A major change since the Middle Ages was the introduction of the ‘general’ or national languages in Europe.
Officially, England is a notorious exception to the known fact that local populations are very reluctant to change their language because it allegedly changed its language from Brythonic to English at a record breaking speed.
Suppose that 2000 years ago all Britons spoke a Brythonic language (proto-Welsh). The
Romans conquered their land, and soon the British upper-class assiduously started to learn Latin. During almost 400 years,
the British aristocracy would help to introduce Latin as a daily language. The example here is Gaul, but also Spain and
According to the CBA (Celtic Britain Assumption), 600 years after the Anglo-Saxon
'invasion', seven different languages were supposed to be present in England :
Pockets of each language should be traceable in local place-names, all over Britain. Logically, in 1166, 100 years after William the Conqueror, a patchwork of languages would have existed. Indications of that situation should have been reported since the early Middle Ages .
Despite this deductive evidence, all the mentioned languages managed to merge in 1366, only 300
years after the conquest by the Normans, into the very recognizable language of Chaucer. Moreover, all traces of languages
other than English had disappeared in England  except for Latin in writing and many French words that had been freshly
introduced. The very presence of those words in English can be understood as a proof that the language was indeed greatly
influenced by Latin and French. But where are the typical Welsh words? They should have been more present if we compare this
with the number of Brythonic words in modern French (although there too, the number has been greatly overestimated). More
words of colonial origin were introduced in the English language than words of Brythonic origin. Australia gave words
like boomerang, kangaroo. America gave words like tomahawk, etc.. English always had the capacity to absorb foreign words.
However, linguists now claim that traces of Brythonic survive in grammatical constructions. This
is possible: we know that it was the language of Mercia that influenced the most Middle English and we know that a part of
Mercia consisted out of former Welsh territory.
By contrast, the original Welsh language remained in Wales, parts of Scotland and
Cornwall and is still well traceable there. Why is there no trace of all other languages in the east of Britain? 
Evolution of English
The evolution of English is presented as if everything started with the oldest texts like Beowulf and then evolved in a straight line into modern English. That is not true. There is a major distance between the language used in the Beowulf poem and Chaucer's English. There were many Old English dialects. There was no such thing as standard Old English. Modern English is a mixture of those ancient local dialects. The question is even whether in those days someone from Wessex could understand someone from Kent.
The version of Beowulf we have is a West Saxon translation of what was probably an
original East Anglian poem . West Saxonia or Wessex is the modern region near Oxford. East Anglia is near Cambridge.
Apart from that, the writing standard of Beowulf is different from later Wessex texts. The language in Beowulf was a local
dialect. It was the language of Mercia (central England) that had the most influence upon later standard English, not
the Wessex language. Therefore, Beowulf cannot be considered to be the precursor of English. Beowulf is
interesting because it illustrates that proto-English was not a single language but a language group.
In Middle English, some ancient Old English sounds had disappeared. For instance: the character
'y' in Old English should be read 'ü' like in the German word Frühstück (breakfast). Or like in
déjà vu, wrongly pronounced 'dayzha voo', which is French for 'already seen'. The sound that comes close
in English is the 'u' like in 'butter', but much more emphasized or like 'oo' in football as spoke by a Scotsman. This
'u'-sound is present in Brythonic, French and in other Germanic languages. It is absent in Spanish, Italian and Latin.
Pronouncing 'y' as it used to be makes Old English sound much more like West Flemish, Frisian and other low Germanic
languages. For instance, 'yfel' is 'evil' and was pronounced like 'uffel' but with a more emphasized 'u'. This 'u'-sound is
completely absent in modern English.
To understand Beowulf better, the poem should be re-written using modern writing standards.
The gap between Old English and Middle English can be understood only when you take into account
the absolutely dominant position of French at the English court in the Middle Ages. Between Old and Middle English stands
French. French was the language of William the Conqueror and soon after the conquest, 75% of the English aristocracy
Language protection is also what happened in Flanders and Germany when they had to accept new concepts of French origin (and the French often got it from the Italians..). Similarly in modern France, when they too have to accept new words coming from England or America. For instance, the French rejected the words computer and byte and proposed 'ordinateur' and 'octet'. And yes, they do have a word for entrepreneur. It is entrepreneur. Recently a German minister declared war against English words in the German language. It was in a similar way that Old English shielded itself from foreign influences.
But after French had become the language par excellence of the English aristocracy, this
sort of protection fell away. The English barons spoke French with a Norman accent in Parliament and only French. English had
become something of the commoners and not worth any attention .
Between 1066 and about 1466, four centuries, English was considered to be a peasant
language in England.  This attitude changed abruptly during the fifteenth century partly because of the
Hundred Years' War with France, and partly because the Black Death tilted the balance of power towards the surviving
peasantry, whose labour became more valuable. So, English became fashionable again, but sadly, the old protection reflex was
gone. From then on, the English intellectuals no longer protected their language, failed to build new compound words and
English evolved into a strange mix of a Germanic foundation and background with a French foreground, mixed with a bunch of
other words, many of Dutch origin. For instance, landscape is such a Dutch word. Without the war with
France, the chances are great that all of England would have spoken a sort of French today. So, all of America would
have spoken this French also.
Eventually, the English aristocracy tried to pick up English again and to give it some high
ranking status again. The result was the birth of an aristocratic sort of English also called 'received pronunciation'. Remember the musical & film "My fair
lady"? Remember "The rain in Spain stays mainly in the plain"? That is what the upper-class usually does: build
a new divergent language that will distinguish them from low-ranking commoners. That upper-class language was Old English at
first, then it was French, later it was stiff-upper-lip English. The first and the last are artificial to some degree.