A little more on y'all redux

[Gordon, Matthew J.]

The only point I'd take issue with from Ron's post is the following:

2. There is little if any linguistic reason (psychological or social) for 
speakers to use "y'all" as a singular, since "you" already exists and "y'all" is 
rather transparently plural given its morphology. Thus one would not EXPECT 
"y'all" to be used as a singular, except maybe in dialect mixture, by outsiders 
trying to sound like insiders.

The development of plural 2nd person pronouns into singulars (often conveying politeness or formality originally) is motivated psychologically and/or socially. We all know about the European examples (English you, French vous, German sie, even Spanish Usted comes from vuestra (2nd person plural possessive) + merced "grace" - I hope I'm remembering this right).  I believe this is common elsewhere in the world as well. And in the French and German cases the polite/formal singular forms retain their plural meanings, so the suggestion that the transparent plurality of one form might prevent it from developing into a singular isn't persuasive.

The development from plural to deferential singular makes sense b/c the plural is less threateningly direct (e.g. "I wasn't talking about just you, I was talking about all yall"). So in talking to a social superior you could use the plural as a more indirect form of address. Eventually the semantic component of plurality is seen as optional and the form comes to mean "polite" singular and maybe eventually just singular. I'm sure others on the list can explain this more eloquently. My point is that,  based on cross-linguistic evidence, we might expect that yall would develop into a (polite) singular eventually. Whether or not it actually has done this is a different issue.

-Matt Gordon