Animals communicate among themselves using they transmit signs, signals or sounds. Communication, like human language, they do not. Even people communicating with each other, do not always use words. People can uniquely Express anger, shrugging in a sign of indifference, shake your head, nod, gesticulate, and more. Many animals with signs or scent can Express the same thing. If a horse neighs or hoof beats, then this is a definite signal to others. Many animals are able to understand the subtle sounds and signals. Dogs can communicate by using different ways. They can bark and howl, growl and whine, teeth bared, or raise a paw. Each such signal is quite clear to others and they know the purpose of that signal in each case. Animals communicate with each other only through gestures and sounds, but also with the smell. This allows herd animals stick together. We all know how important it is for dogs. Monkeys seem to be the most intelligent, but the language is no better than other animals. They use sounds and facial expressions showing feelings of hunger, pleasure or anger. But nothing like human speech, they do not.
Animals understand their language from birth, the man has to learn to talk. Animals can emit the appropriate signals, even if you have never communicated with their own kind. But even communicating with each other, animals Express only feelings and aspirations, and not talking really.