#9 --"You" goes as far back as English can be traced. Ye/you was the plural, with thou/thee the singular.
In Shakespeare they are used as tu and vous are used in French. It's worth paying attention to. No one says "you" to a servant or to someone he wishes to insult. (And of course no one says "thou" to a group.)
Thou/thee didn't become quite extinct until sometime in the 18th century. And the Quakers of course refused even later than that to call anyone "you" since it implied that all of God's children were not equal, going on saying "thee" until quite recently; Richard Nixon's Quaker mother said "thee".

