[Just found this, a pretty rough first draft from a while back. I straightened it out a bit.]
The Lion In Winter would be a lot less Lion In Winter without all that beautiful English, which in all likelihood none of the characters personally could speak much of, if any. Rather all the soliloquies would have been intoned in a variety of the French languages at the time. Peter O’Toole’s Henry II would recite his in Norman (which was the language of the English royal court till Henry IV was raised speaking English instead of Norman French a couple centuries later). Katherine Hepburn’s Eleanor of Aquitaine would recite hers in Poitevin, and Anthony Hopkins’ Richard I in Occitan. I’ve no idea what form of French Geoffrey connived and young John sniveled in. Philip II, I assume, was speaking what eventually became standard French though doubtless he could make himself understood in a variety of the regional Frenches of the north, though perhaps Richard I’s Occitan would have been a stretch. I’m not sure what language mistress Alais did her sulking in, she was raised everywhere by everybody. Any of the above, I suppose, and as she’d been spent some of her childhood in England she probably picked up some English from the household help. In what tongue the various characters would have sniped, raged, conspired and hit on each other with is anybody’s guess. Various of the Frenches, mostly, though Henry II and Eleanor both were fully conversant and literate in the Medieval Latin of the time (which is considerably closer to the Latin of the Catholic mass than the Latin of Caesar’s Commentaries), which would have been useful in front of the children. Qui auditunt quod stupri nocte?
Despite the characters enunciating some of the most glorious English you will ever hear on film—“he came down from the north with a mind like Aristotle and a form like mortal sin; we shattered the Commandments on the spot”—it’s unlikely that any of the characters could utter more than a smattering of English. Henry II probably knew enough so that on some rare trip across the Channel he could order some of the peasants to do this or that, or curse like in Beowulf, or say something filthy to a maid in the market. Otherwise the only character in the whole of the film that would actually be fluent in English would have been William Marshall, who spends the movie scurrying about obeying Peter O’Toole or arresting people. He’s the character you forget. O’Toole’s Henry II, though, is unforgettable. “I hope we never die!” he bellows at the close as only Peter O’Toole can bellow. “Do you think there’s a chance of it?” Alas, there wasn’t, he was gone soon enough, as was Eleanor, though she died at eighty or so, and would’ve been a sixty something at the time of this story (A Lion In Winter had to fudge the chronology there.) Indeed every man of royal blood in the story was gone soon, beginning with Geoffrey, trampled to death at a jousting tournament. It’s William Marshall among the men who came close to never dying, by medieval standards anyway, outliving Henry and his sons by decades. He died in his bed at 72 and was buried with honor in London, the mass said in Latin, the eulogies in French, the throng of onlookers murmuring in English.
It would be two centuries before an English king could bellow at his wife and sons in the same language as Chaucer, another couple centuries till an English speaker could rage like Lawrence Olivier’s Richard II raged three centuries after that, and it’d be deep into the twentieth century before they could bellow like they bellowed in The Lion In Winter, a high medieval Francophone drama spoken in twentieth century English.