I'm...Confused? :/

Remember that in the movie 'Wrong Turn 2' the so called survivors always yelled at the Cannibal Hillbillies and used swear words and shit (not that I'm against it 或者 something, I'd do the same)...
So yeah, what I'm asking here is:

Do the Hillbillies actually understand them? Because they always got pissed and attacked the survivors if they yelled at them...Or maybe they just reacted to the tone that the survivors used? Ya know, like Animals?