Somewhat off topic, semi-related, I have a bat that thinks I control the weather. If it gets too hot or cold, it will go just outside my window and squeak at me. There are patterns to it's communication, though I have no idea what exactly it is saying. I can talk to it and it talks back. Obviously we don't understand each other. I can tell it "get back to work" (taking out mosquito's) and it will leave. I think it understands tone of human voice.