My folk must have welcomed your folk. One family was in Maryland in 1720 and then moved to VA before 1723. (Maryland is south of Mason-Dixon line.) They ended up in Tennessee, Georgia and Alabama. Another was in VA in 1656. They also ended up in AL.
Here is a fun write up of “y’all”.
http://en.wikipedia.org/wiki/Y’all
Y’all is also used in the phrase “all y’all”, which is a more inclusive form comparable to “all of you”. This can cause some amusement as “all y’all” can be interpreted as “all of you all”. Note that we can be used as the first-person analog of y’all for the first three properties listed above.
Thanks for the write up.