Originally thou was to you as in French tu is to vous. Thou signified either close familiarity or social inferiority, while you was the more impersonal and general term. In European languages to this day choosing between the two forms can present a very real social agony. As Jespersen, a Dane who appreciated these things, put it: “English has thus attained the only manner of address worthy of a nation that respects the elementary rights of each individual”
