That sounds so familiar… the dogs we had when I was in college came to recognize the word “pizza” when we were talking about ordering it. (It probably didn’t help that they’d get tiny tastes of it when it came.) We started spelling it out instead. So, as you can guess, they learned that too. 
It’s the same with the dog we have now-- it’s gotten to the point that I leave the room to call in an order, because if she hears me call it in, she gets excited and watches the door. Dogs can be smart, especially when it comes to food.
