Number of adjectives in polite plural address

Question

This question concerns using the plural vos instead of the singular tu for polite address of a single person in Latin. This is not a classical feature but arises later.

When using this address, are the adjectives and participles referring to the addressee in singular or plural? My starting point is what we do in Finnish, transformed directly into Latin:

• Regular plural: Vos estis Romani/fati. (Te olette roomalaisia/puhuneet.)
• Polite singular: Vos estis Romanus/fatus. (Te olette roomalainen/puhunut.)

In Finnish there is a discrepancy in polite singular address: the pluralization only applies to personal forms of verbs, not to adjectives or participles. Does the same discrepancy appear in Latin?

I think it has to be there for nouns. It makes little sense to say vos estis reges to say politely "you are a king", so I would expect vos estis rex. But with participles and adjectives I feel it could go either way. Which way does it go? Are there perhaps examples of both?

Answer 1

I offer this as a partial answer to Joonas’s question.

In French, or at least in the written form of the language, you write “vous êtes content” for “you (polite singular) are content”, but “vous êtes contents” for “you (plural) are content”. However, in the spoken language there is no difference between “content” and “contents”, so both sentences sound the same.

I cannot think of any language that uses a plural adjective as the predicate of a plural pronoun when the latter refers to a singular person. German does not help; “Sie sind zufrieden” can mean either “You (polite)…” or “they…”, but this is because in German predicate adjectives are invariable for number and gender.