As far as I know, you actually is the formal, originally plural version (ye/you/your) and thou was the informal version (thou/thee/thy/thine). Over time, thou b

As far as I know, you actually is the formal, originally plural version (ye/you/your) and thou was the informal version (thou/thee/thy/thine). Over time, thou became impolitely informal and is now no longer used, though interestingly enough, nowadays it might even be perceived as more formal than you because it's archaic and survives almost exclusively in liturgical language.