Actually, I think it is capitalized. The same word means "they", so perhaps that's a distinction. The thing is, nobody uses De unless they're talking to the queen, so I'm not too sure.

At Oxford they number people according to the year of matriculation. It might be due to some courses being 3 years, whereas others are 4 (or even 6 for medicine).

Well, I know in Vietnamese (and Chinese) there's a whole load of different words used to address someone, depending on whether you're younger than them, your father is older than them, etc, etc. I was thinking of a formal address towards an unfamiliar stranger though.

So, politeness inflation means there's only one form now? What about the PIE question? Is the formal form of address specific to PIE? I can't think of analogous forms in Chinese or Vietnamese, and I don't know enough about any other languages...