Animals are generally good at understanding that not everyone is them.
A great example is the best animal: The House Cat. Cats are pretty famous for catering their sounds to different targets. Mom not paying attention? Squeaky cry. Something needs to be taught who the big err... cat is? Growl. Content and happy? Purr.
Need something from a human? Meow. Because they understand that humans don't understand purrs and body language to the same degree.