Impostrophe

In Texas I learned the word y'all. I had more than one discussion with people about where the apostrophe goes in the word. Some said that it went after the 'a' (ya'll). I searched out to study the right answer, and I learned that the apostrophe goes where the letter is left out, which y'all know that I was right. The real question is plural possessives though. If the word is already plural, children's, then the apostrophe goes before. If it is singular, boys', then it goes after. Interesting. To learn mor', click right here.