Since the beginning of the long partnership between dogs and humans, dogs’ ability to understand large numbers of words has fascinated humans, tantalizing them with the thought of a talking dog. But dogs will never talk or otherwise communicate with words, not because they don’t understand words, but because they don’t think in words. No matter how many times Thor heard the word, “yes,” no matter how well he understood its meaning, he would never think “yes” when asked if he was hungry, or if he wanted to go out. He might feel yes with every cell in his body, but his mind would never “speak” the word, the way human minds do.