Heh Roman's like that.
I don't think he actually knows most of his commands. He guesses by the context and my body language. Whatever. It works 95% of the time. I can point him in a direction and say "Go over there" and then say "Get it, bring it here" and he'll start picking up and dropping things in his vicinity, waiting for the yes marker. He doesn't actually know what I want, but he gets that I want something, and that something is probably nearby, and when I say yes, he's got the right thing. Of course I use "get it" and "bring it here" for his actual toys, sticks, balls, etc. So sometimes I'll try and get him to pick up something random and he'll try going for the stick he was just playing with, so I'll tell him "no" and to "go get it." It's kinda like the game hotter, colder.
The guessing is handy for training sometimes. For instance, I wanted to teach him rollover. I told him "side" (lie flat on your side) and he'd do that, then I repeated the command and he started trying new things, rolling onto his back, then he rolled totally over. yesss. good dog. I did something similar to teach him "paw."
He's not so well trained and secure in his commands that I can tell him to "side" 5 times and he'll remain flat. By the second or third time I give a command he's offering other behaviors.