Man, this guy has great content and I've tried to get past his speech impediment for literally years but I can't. It really taints his videos unfortunately.
At first, I just thought it was some kind of exotic accent but I have had no problem understanding him and english is not my first language. In fact, I find his speech quite enjoyable.
So to anyone unfamiliar with his work, do not let this stop you from watching, it's awesome if you are in to this kind of stuff.