So I read "The adventures of English" by Melvyn Bragg. The book is a history of the English language from its German roots towards modern times. I discovered that "dales" is actually a word from the Vikings.
Also I didn't know that the black death plague (around 1348) had a good consequence. It killed many of the "masters" of the land, who spoke French, and also killed many of the clergy who spoke Latin. Yes, the Kings of England spoke french after the Norman invasion in 1066. English was the language of the masses of Britains.