Bookwyrm627: "Ya'll" is the second person plural. For some reason, people not in southern USA don't seem to like it.
Wishbone: And according to Jeff Foxworthy, "Youance" is y'all +3, just about.
Besides "you-all" ("y'all"), apparently "youse" and "you-uns" (and probably others) are in use in certain parts of the U.S. I know "youse" is used in Ireland and apparently parts of Britain, and there are probably other "nonstandard" terms used in various English-speaking countries.
The interesting thing is, English
did used to have proper second person plural pronouns, and lost them. I know "you" was at one time used more or less exclusively for that purpose, with "thou" being the singular form; and in a different time period (I think later) "ye" filled that role instead, as at that time "thou" and "you" were both singular, with one being for more formal use or addressing one's social superior ("you"), and the other being more casual, or for addressing someone beneath one's own station ("thou").
Sorry for the blather. I just find this sort of topic fascinating!