Okay, slightly off topic, but I just had to share.
One of my cats, Beast, is a beautiful, regal tuxedo cat, and is probably the largest house cat you've ever seen, with the possible exception of some Maine coons. He is a huge chow hound, plus he eats whatever he can catch. The vet insists that I keep him on a diet, and so Beast is always hungry, always begging, and has learned how to really work Kosta, my husband (who is admittedly a soft touch) for food, even when I've already fed him. But the schedule is that Beast is fed twice a day, once when I get up in the morning (anywhere from 4:30 to 6:30 AM) and at 6PM, and Beast knows this.
Today, Kosta and I had an appointment out of the house in the late afternoon, and so were leaving at 4:00. As we left, we locked up the house, which includes closing the back door, which is basically left open (except for the screen door) all summer, whenever I'm home. Beast was lounging out on the back deck, and when he heard us, he came running for the door Kosta held open for him.
"He thinks he's gonna get fed," said Kosta as Beast trotted through the door.
I replied, "He's not gonna," as I locked a nearby window.
And Beast literally made a U turn and trotted back out the still open door!
Is there any doubt in your mind that Beast understands human language?