Sorry Rob, I omitted any further explanation because morris is translating a book about numerology, and he's translating everything as addressing public, thus voi. Voi used for a single person is very very oldfashioned and used mainly in some dialects. As an example, I know that one of my (acquired? I don't know the proper word) uncles, who's 60 something, addresses his mother with vu (he's originally from Cremona). Weird uh?