They do talk while wrestling. It's a long drawn out "Aaaaahhhhrrrrrrr". Like in the first picture, they talk but don't bite.
Also, if you look closer to the second picture, Digger has his foot on Dozer's neck. I took the picture just as he pushed Dozer over.
Charlie is an only 4 legged child at our house, so he plays with us like that, with open mouth. Our daughter was playing with him one evening and he accidently hit her cheek with his teeth, and now she has what looks like a bite mark on her face. He was so upset that he wouldn't even get near her for several days. But we're not mad at him it was just play--he is not agressive at all!!
Mine are just as nutty! But normally one is on the floor while the other one is taking cheap shots at the legs and neck. But it is all in good fun. And they are very loud. Since I have three dogs one stands and referee's(sp?) the roughness. They must take a lot of cheap shots because the one not playing is always doing a lot of barking. I just laugh and think it is great!