Cats may not understand human language, as we do. But they are very good with patterns, and perhaps that's the same thing. When I ask, "Do you want to go out?", they will go to the backdoor and wait, or the window if I'm upstairs. When I ask, "Do you want to eat?", they will go to their food bowl if they're hungry; otherwise, they'll ignore me. If I ask, "Do you want to play?", they will get in a position to play, which usually means the Da Bird. It helps when the emphasis is on the last word: OUT, EAT, PLAY, and if I simply use the last word, such as "Out?", it will get the same reaction. The question inflection helps too, because I get a different reaction if I say, "Get OUT of the refrigerator!". The cat won't necessarily get out of the refrigerator but neither does she take it as an invitation to go outdoors.