re: Communication
There are certain levels of communication that work on animals, usually just versions of what they use themselves. When dealing with great apes, there are certain postures, noises, and other signals that scientists have learned to use to ease their observations of nervous animals.
Progress in using sign language and other methods with gorillas may or may not be true communication involving abstracts. I've seen arguments both ways.
Other animal trainers have learned to use the same signals that animals use themselves. You whap a puppy lightly to teach it "no" not because hitting puppies is cool, but because the puppy's mother makes the same point with a harmless nip.