*I believe those of the U.S. closer to the southern hills differentiate these with tis, thar, yer/yur and yor, respectively...
That is not as far off the mark as you think.
Standard English does not differentiate between "you" (singular) and "you" (plural).
It it correct to say:
"Would you (John) like to visit me on Saturday?" and
"Would you (John and your family) like to visit me on Saturday?"
In the Southern United States you would say:
"Would you (singular) like to come over for the game on Saturday?" or
"Would y'all (plural, bring the family, we're cooking a pig) like to come over for the game on Saturday?".
In the Northeast United States you would say:
"You (singular) want to come over for the game on Saturday?" or
"Youse (plural) coming over for the game on Saturday?