I see outward bound communication as a specialized action. It differs from typical physical action in the primary consequences of that action. Typical physical actions result in locomotion, feeding, or mating. Communication actions have effects on others. One might see them as forms of advertising. They might attract mates, frighten possible prey into immobility or predictable actions, or convince predators that one is inedible or dangerous.
As a skill, the communications activity must be repeatable and may depend on perceptions. Innate communication skills must also be similar across most members of the species.