Maybe it's a sign of senility, or maybe she thinks they actually understand what she's saying. Whatever the reason, mom is yelling at the dogs-again. I'm not against yelling at dogs when they've done something wrong. In fact, it helps them learn. But the way mom yells at them, you'd think they were going to respond back.
When the dogs do something like, I don't know, eat the sandwich off of my plate, which they've done many times, I would just say No! Bad Dog! But my mom, she would yell No! You bad dog! How could you do this?!? You don't do that! You don't do that! You don't steal sandwiches off of our plates! or something along that context. It's almost as if she thinks they understand what those words mean, when in fact they only understand the tone. They could pee in the house and you could yell the Emancipation Proclaimation at them, and in two weeks, they'd be housebroken. Anyway, I'm not saying it's a bad thing, but seriously, they can't understand you. After all, when you take the time to make sure you use the correct form of have when speaking to a dog, you're just wasting breathe.