I learned French and they have a singular "tu" and a plural "vous" that English is lacking.

English used to use "thee" as the "tu" form, but that was dropped for the more formal "you" or "vous" form. Y'all takes the place of plural "you", so that you know if you are talking about one person or a group of people.

You guys tries that, but it's two syllables, and you may have girls in your group.