Many animal and even plant species are said to ‘communicate’ with each other. Humans are not unique in this capability. However, human language is unique in being a symbolic communication system that is learned instead of biologically inherited.
Symbols are sounds or things which have meaning given to them by the users. Originally, the meaning is arbitrarily assigned. For instance, the English word "dog" does not in any way physically resemble the animal it stands for. All symbols have a material form but the meaning can not be discovered by mere sensory examination of their forms. They are abstractions.
A major advantage of human language being a learned symbolic communication system is that it is infinitely flexible. Meanings can be changed and new symbols created. This is evidenced by the fact that new words are invented daily and the meaning of old ones change.
Languages evolve in response to changing historical and social conditions. Some language transformations typically occur in a generation or less. For instance, the slang words used by your parents were very likely different from those that you use today. You also probably are familiar with many technical terms, such as "text messaging" and "high definition TV", that were not in general use even a decade ago.