The English are the people who live in England. What exactly one means by "England" can vary quite a bit depending on what year it is and who's talking.
English is a West Germanic language spoken as an official language in a number of countries. Its importance during period was little, with Latin and French being the major languages used for politics and science.
As many as half the words in modern English come from Latin (some via Greek) and a great many French words were introduced as a result of the Norman invasion of England during 1066. Little is known of the English spoken in the years immediately after the Norman conquest as official matters were either written in Norman French or Latin. When English did start to appear again there became apparent a class divide in the vocabulary. For instance shepherds took care of Germanic sheep, but nobles were served with French mutton. In spite of the massive impact that Norman French had on English, English is still very much a Germanic language, having retained many grammatical features as well as ninety percent of its core vocabulary.
It is easy for speakers of Modern English to read text that was produced in the years after around 1400 AD but earlier English is almost unintelligible. The article on Old English provides good examples of this.