Would there be any benefit to reviving the archaic pronoun thou and its other forms? Originally a way of conveying familiarity, intimacy, or even disrespect in some cases, thou was the singular form of the word “you.” It provided a similar dichotomy that other European languages have: in French tu/vous can be translated as thou/you.
These days thou is archaic, but it persists in daily speech in some parts of the world: regional dialects in Scotland, for example, and among the Society of Friends (Quakers).
For most English speakers, however, it has completely lost the aura of intimacy it once had and instead seems stiff, formal, and ritualistic due to its use in religious texts. We still see thou used in some modern contexts: Thor in Marvel Comics is a regular thou-user, and we hear Darth Vader ask of Emperor Palpatine, “What is thy bidding, my master?”
With the increasing acceptance of non-binary third person pronouns [such as they or ke or ze], might thou also find new life?