More than One
When the Pronoun Committee met in Amber and Igor’s cave, it realized another universal truth:
Often there would be more than one speaker, more than one listener, and more than one unfortunate soul being talked about.
So in addition to singular pronouns, the esteemed committee devised plural pronouns.
The string of pronouns for the singular first person I-me-my-mine was joined by its plural counterpart we-us-our-ours.
The singular second person you-you-your-yours gained its plural you-you-your-yours (which turned out to be identical, but only if one ignores the southern y’all-y’all-y’all’s-y’alls or the northern youse-youse-youse’s-youses).
And the singular third person he-she-it/him-her-it/his-his,her-hers,its-its received its plural they-them-their-theirs.