All animals engage in some form of communication, but humans are the only animals that have language. It is a feature that has facilitated the cultural evolution of the human species over thousands of years. What sets language apart from other forms of communication?
Its a shared system of arbitrary symbols that refer to things
It has rules (or syntax) that govern how symbols can be arranged
It is generative, meaning that symbols can be combined to produce an infinite amount of ideas
Language development starts in infancy. Newborn babies are able to distinguish their mothers' voices from others, are able to perceive different emotions based on the inflection and volume of speech, and can hear speech contrasts in any language. By the age of one, infants have lost this ability and can only hear speech contrasts of their native language. Although the language we ultimately speak is determined by our environment (and the arbitrary symbols used in any language are entirely a production of interactions with other humans), there is also a clear biological component. The capacity to learn, comprehend, and generate language is an innate ability that is unique to human beings. Moreover, there is a timeframe in which this learning must occur. Research shows that if children have no exposure to language until after puberty, they are not able to learn language at all. The younger they are exposed, the better their chances were.
This funny clip from Lost in Translation(2003) demonstrates how important a common language is to effective communication, and how much nuance can be lost when one language is translated into another.