I am sure Penny understands quite a lot of words which we use in general conversation with each other, not directed at her. For example, if when visiting a friend, I say to the friend," well Id better go home now" Penny runs for the door. If we mention our sons names, ( who often visit) she will also often go to the window to look out for them. She seems to know when we are preparing a dinner for visitors, as she will wait at the window for the visitors to arrive, instead of following us around begging for scraps of food. I swear she also knows the meaning of the word "hungry" as when any of us use it in conversation she runs to the fridge. There's lots of other examples. We haven't taught her any of this . She's just picked it up.