I would go even further to OP's title. Dogs especially, although most animals have it too. It's not so much the words..it's how it is said, the body language you emanate, the actual energy you produce. Often, they will react to you even when words aren't uttered. Ala~ sick, sad,depressed, upset and controlling anger. They seem to react and respond accordingly.
Oh yeah, they also react to routine activities, sounds of a leash, getting ready for work, going to kitchen and getting their food ready etc etc etc. My fur baby (RIP
sweet one) would automatically get into his kennel when I was preparing to goto work. It's uncanny how these animals seem to know even before you do what your next move is