1. normally at the end of a comment to ask if person has understood.
2. Can also be used as an agressive tone to mean "do as i say/do"
(that girl is very nice to look at, you agree?)
2. "stop that you fool! do it this way... yearin!"
(your doing it wrong do it like this!)
"go get the bike from sammy now!.. yearin!"
(go get the bike off sammy!)