this "yargyblarg" is the language that the characters named "elites" speek, made up by kids on xbox live, has now became a somewhat funny statement to shout, normally used for making others laugh, or used to create a realm of silence once shouted!
guy 1: YARGYBLARG!!!
*camera zooms in on an elite*
"yargyblarg, blarg blarg yargz yargyness blarg"