Of course the concept of nationality has evolved over time, but it seems strange that no one questions the fact that someone obviously English has the very German name of Ulrich von Liechtenstein and claims to be from Gelderland. Granted, Hollywood tends to play fast and loose with not specifying what language characters are actually meant to be speaking in, but there's no indication of the main characters trying to pretend to be anything but English. Would it have been perfectly normal for someone from one country to have a completely foreign name, along the 14th-century jousting circuit?
Note: I don't mean any criticism of A Knight's Tale, which is of course the second-greatest sports movie ever made, after Major League.
Would it have been perfectly normal for someone from one country to have a completely foreign name, along the 14th-century jousting circuit?
Actually yes. During the medieval era, the nobility was not tied to the land and their prestige followed titles (which may or may not be tied to land). As society's elite, they were more mobile in their fortunes and residences. Furthermore, nobility did not always speak the same language as their regional subjects. Putting the film's charade aside, it's possible to have say, a surname originating from one region, their native tongue of another culture, and possessing lands in an entirely different county. It was more common to have just two of those, though. One notable example is the Norman Invasion of England in 1066. The result was French/Norman speaking nobles with ties to the continent (French/Norman surnames), yet ruled in a land that spoke mostly Anglo-Saxon. By the 1300s, some of the descendants would be English speaking, with a French surname, ruling over English, Irish, Scots, and Welsh. The Crusades also saw French speaking knights, who were born in England, holding lands in the Levant who's population spoke a variety of languages.
One modern comparison might be how an English upper manager is in charge of a company with an HQ in Germany but originally had a French name, and the majority of the employees are in France. As you can see, the higher levels are more fluid.
You're correct that our idea of nationality and statehood was different than Europeans in the 1300s. The King of France had long been more akin to "King of the Franks", who reside in a region formerly known as Gallia Lugdunensis, Gallia Aquitania, Gallia Narbonensis, and so on; and now known as Francia (land of the Franks) due to the Franks living there. People were ruled by dynasties more than the political offices and governments themselves. There were direct, personal ties to government; such is the way of monarchy. This was a time when questions like "what is it to be English?" were beginning to take hold, and people were only beginning to identify themselves on national levels. It still had centuries of development to go, though. As titles were held by individuals and dynasties, it was entirely possible for the many in the ruling class to be very foreign from their lands. Of this there are incredible amounts of examples. One would be French speaking Charles I of Hungary of the Anjou Dynasty (a Capetian Branch), who was from Salerno, Italy; and became monarch of Hungary.
As for the film's actual charade of a peasant impersonating a knight, I'm going to refer to these posts concerning questions of individual identity and impersonations.
A very recent thread about forgeries by resident commentators:
After reviewing all of which, the premise of the film and the nature of the charades, we really only know the ones that were 1. written down and 2. exposed or had their credibility seriously doubted. Did people impersonate others and have fabricated/fraudulent titles/positions? Of course. It seems the more notorious and higher level the fraud becomes, the more difficult and unlikely it will work. Getting into specific situations such as a commoner impersonating a foreign knight become speculative. Maybe another reader will have a specific example.
The Age of Plantagenet and Valois by Kenneth Fowler
The Penguin History of Medieval Europe by Maurice Keen
Judith Bennet, C. Warren Hollister - Medieval Europe: A Short History
R.H.C. Davis, A History of Medieval Europe
The Crusades: A History by Jonathan Riley-Smith