Originally a hindi word used for a informal form of "let's go".
Now spread cross culturally used to mean anything from "okay", "yes", "no", "really?", "what??", "let's do it", "oh" etc.
May be used as a verbal fullstop. Can be used in most
situations depending on intonation.
Will make you sound slightly fobby.
Started becoming used in a widespread manner in
Australia from January 2010.