you

You was originally the accusative and dative form of ye ‘you’, but it began to take over as the nominative form in the 15th century, and at the same time was in the process of ousting the singular thou to become the general second-person pronoun. Its west Germanic ancestor *iwwiz, which also produced German euch and Dutch u, went back ultimately to Indo-European *ju (source also of Greek úmme, Sanskrit yūyám, and Lithuanian jūs). Your (OE) comes from the same source, with the genitive ending -er.