they are speaking Russian. in the start the camera guy (i think) says "i ain't jumping, i ain't stupid enough" when the 2nd guy tries to jump he says "are u a fucking dumb ass jumping in for him"
and then wen the 2nd guy jumps he says "what a bunch of retards"
.....like Albert Einstein said "a definition of stupidity is when one keeps redoing the same thing hoping for a different result each time"