It seems to me that some pets are actively interested in what we say to them, and they try to understand everything we tell them. Others just kind of listen when they think it might be something that is important to them, like "do you want a snack?" kind of a question.
Chipper seemms like he listens to everything that i am saying ,even when i am not talking dirctly to him, he is paying attention. If my husband says he is thinking about going to bed, then Chipper is listening, and knows it is time for his last little trip outside before bedtime.
Tootsie pays absolutely no attention to anything, unless she thinks it involves her, or food of some sort. It has taken her months to figure out what "go do your chores" means, although she perfectly well understands that when Chipper goes to the bathroom, they can come back in. She would watch him, instead of doing that herself, and then look at me as if to say they were all done now.
She doesn't try to communicate or interact at all, like chipper does, yet, I know that she is a very intelligent little dog. She just isn't interested, I guess.