When they arrive to Paris the crew bet against a group of frenchmen that Sir Ulrich will win and not a frenchmen, this then becomes a french vs british discusion... but Sir Ulrich isn't british, he is from Gelderland...
European nobility is an extremely complex issue, with titles passed through marriage and inheritance and appointment, and it was (And still is) extremely common for people "from" a certain place to have spent very little, or even no, time there. As a "for example," Richard the Lionheart, despite being one of the most famous Kings of England, was French and spent less than six months of his entire life in England. He didn't even speak English. In fact, many monarchs of England didn't speak English, with many of them only fluent in French or German, and they didn't even consider themselves English despite ruling the country. The reverse happened many times as well. A Englishman inheriting Gelderland titles would have been nothing out of the ordinary.
Yesh La-Malachim Ha-Ta Telefon The angels have the phone box
But in a movie such as A Knight's Tale which gleefully flaunts its anachronisms left, right and centre, should a discussion on alleged plot holes even be raised?
No, "Ulrich" (actually William) REALLY is English. The Gelderland thing is a ruse, remember? And his friends are so full of their victory over the French, THEY forget that Ulrich isn't supposed to be English.
If the screenwriters had been a bit more clever, they would have used this episode as what first aroused Ademar's suspicions that Ulrich wasn't who he said he was.
"You didn't come into this life just to sit around on a dugout bench, did ya?" - Morris Buttermaker
As was stated above, European nobility can be quite complicated. Just because you are British, doesn't mean you can't be French or Spanish nobility, for example. In fact, the real "Black Prince" was not only a British prince, but also the Prince of Aquataine, which is a region of France.
Interesting. I think the bigger plot hole may be the language of nobility at that time & its significance. French language was introduced to England with the Norman conquest in 1066. Anglo-Norman French was the mother-tongue of the upper class well into the 14th century; if not longer. The nobility were typically multilingual. A knight, given his nobility, would converse in Anglo-Norman French. My only hesitation with this plot hole is the setting of around 1356 since this is also the time English began to eclipse Anglo-Norman French through assimilation. Although, Count Adhemar, given his dislike & suspicion of Ulric (William), could have discovered the deception by speaking to William in Anglo-Norman French...but then we wouldn't have the movie as it is today. I can live with this seeming plot hole.
It is nice to be important, but it is more important to be nice. ~ John Templeton
Considering that he has traveled with Sir Ector for 12 years, he probably would speak French. He wanted to be a knight, so my guess is he would either learn the language from Sir Ector directly or simply from interacting with people over the course of his travels. He would not have to be flawlessly fluent in the language to be passable, especially as many, like Adhemar, would probably consider him to be a back country knight with limited education.
King Henry iv was the first king to speak English as a native language. He died in 1413. Much of the nobility (not royalty) would speak both Norman French and English because they would have to speak with household servants that would only speak English.
After Henry IV took the throne, speaking Norman French would have fallen out of use in Court.
I think its a good scene- including most of the smart comments here, what is identity anyway? At least three of the maim protagonists play with their identity while making ammends with their past or secret habits - and here are three drunks who shout against another three drunks like soccerfans in a pub - cool realistic scene. Fits to the timbre of the movie.