A noise or words (Depends at how you look at it) used when you are so filled with an emotion, good or bad, that words fail to describe it.
Guy 1: Hey dude, you look a bit rough what's up?
Guy 2: Well it's just all this stuff... And then there's more stuff and... Rargle flargle...
Guy 1: That bad, huh?
Guy 1: You look happy, why for?
Guy 2: Ah, I just, y'know... Ah... Rargle flargle
Guy 1: Good enough for me