This is a British television series (ITV) on the history of the English presented by Melvyn Bragg. There is an excellent a companion book, also written by Bragg. The series ran in 2003.
The series and the book are cast as an adventure story, or the biography of English as if it were a living being, covering the history of the language from its modest beginnings around 500 AD as a minor Germanic dialect to its rise as a truly established global language.
In this episode, we find out how the English language got its rules of "proper" English.