英式英语和美式英语产生的不同背景

Historical Background of British and American English
The history of the English language is divided into three periods: The period from 450 to 1150 is known as the Old English. It is described as the period of full inflections,since during most of this period the case ending of the noun, the adjective and the conjugation of the verb were not weakened. Old English was a highly inflected language. It had a complete system of declensions with four case and conjugations. So Old English grammar differs from Modern English grammar in these aspects.
The period from 1150 is known as the Middle English period. It is know as the period inflections. This period was marked by important changes in the English language. The Norman Conquest was the cause of these changes. The change of this period had a great effect on both grammar and vocabulary. In this period many Old English words were lost, but thousands of words borrowed from French and Latin appeared in the English vocabul