(1) Had English been designed rather than simply evolved, we probably would have hung on to some form of address other than “you” to simplify our lives. “You” was originally an object pronoun. “Ye” was the nominative or subject pronoun. For example, in the Authorized (King James) Version of the New Testament, in First Corinthians 3:16, you read: “Know ye not that ye are the temple of God, and that the spirit of God dwelleth within you?” (Two are nominative (subject) and the third is accusative (object).) The “ye” has fallen by the wayside, and “you” does double duty in modern times as both object pronoun and subject pronoun. Perhaps the next to go will be “I” so that we will use “me” for everything: “Hello, it’s me.”
(2) Even today it is potentially confusing to have the same second person form for both singular and plural. (In German and French, where the second person plural is also used in the singular as an intermediate polite form, the second person singular verb form is different, so there’s no ambiguity.) One American accommodation is to add “-all” to the end of “you” when used in the plural, or in the deep South, “y’all.” But then, perversely, in the Deep South, “y’all” is often used in the singular, thus neutralizing the fix! This illustrates how dynamic language can be, especially among those who do not worry much about whether or not they are speaking correctly.
One More Thing:
FYI — The “Ye” in signs like “Ye Olde Taco House” has nothing to do with the archaic nominative form of “you.” The “Y” in that “Ye” is a modern alphabetic approximation of a different letter, one that was used in the Old English alphabet (and is still in use in Icelandic today). It is called a “thorn” and is pronounced “th.” Thus “Ye Olde” should be pronounced “The Old.” Now you know; you won’t ever make this ignorant mistake (except on purpose), I hope.
This is what a thorn looks like: It’s hard to tell from the printed form why typesetters started to substitute a “y” for it when they no longer had “thorn” in their font cases. It looks like a “p” superimposed on a “b.” The handwritten form of the “thorn,” however, often looked like a “y,” with the tail on the left of the “cup” instead of on the right.