This article in Leeds Today, on the forgotten St. Edmund, says they did:
In the wake of the Norman Conquest of 1066, everything connected to the English nation and its culture were suppressed – especially the language, literature, and flags. French became the language of everyday life. . . . [N]ot until the reign of Henry VIII was it in more general use across the country.
This is clearly false, as any medieval English literature textbook will suggest — it's all about The Owl and the Nightingale, King Horn, Chaucer, Gower, Langland, Sir Gawain and the Green Knight, Margery Kempe, Richard Rolle, Malory, etc., etc., etc. — all works in English, not French. O.K., so it doesn't answer the question to refer you to a Middle English handbook — where are all the literature-of-England-in-French handbooks? Still, the point is that this is popular literature.
Moreover, from the medieval experts over at Wikipedia, we see (oomphasis added):
Middle English was one of the five languages current in England. Though never the language of the Roman Catholic Church, which was always Latin, it lost status as a language of courtly life, literature and documentation, being largely supplanted by Anglo-Norman French. It remained, though, the spoken language of the majority, and may be regarded as the only true vernacular language of most English people after about the mid-12th century, with Anglo-Norman becoming, like Latin, a learned tongue of the court. Welsh and Cornish were also used as spoken vernaculars in the far west.
English did not cease to be used in the court: it retained a cartulary function (being the language used in royal charters); nor did it disappear as a language of literary production. Even during what has been called the 'lost' period of English literary history, the late 11th to mid-12th century, Old English texts, especially homilies, saints' lives and grammatical texts, continued to be copied, used and adapted by scribes. From the later 12th and 13th century there survive huge amounts of written material of various forms, from lyrics to saints' lives, devotional manuals to histories, encyclopaedias to poems of moral (and often immoral) discussion and debate, though much of this material remains unstudied, in part because it evades or defies modern, arguably quite restricted, categorisations of literature.
Middle English is more familiar to us as the language of Ricardian Poetry and its followers, the 14th- and 15th-century literature cultures clustered around the West Midlands and around London and East Anglia. This includes the works of William Langland, the Gawain Poet, Geoffrey Chaucer, Lydgate, Gower, Malory, Caxton, and Hoccleve. Perhaps best known, of course, is Chaucer himself in his Canterbury Tales and other shorter poems, where the poet consistently revalues and reinvents older traditions while managing to avoid completely abandoning them.
Later on, the article explains how Norman French influenced English grammar, for instance playing a part in helping English shed its inflected forms. Even so, it says, this change "cannot be attributed simply to the influence of French-speaking layers of the population. English remained, after all, the language of the majority."
Just another reminder that you should beware of what you read in the popular press. (And this is something that it doesn't take that much knowledge to realize is wrong: The regular folks in the whole country started speaking the language of aristocrats? And went back to the previous language 500 years later?) To his credit, the author very graciously admitted his inexpertise.