Language is the use of a biologically immediate artifact to represent something that is not biologically immediate.
All organisms, including humans, exist only within biological immediacy. That which is removed in space, that which is remote in the past or future, that which is not graspable through innate biological capacity—such events cannot be directly engaged or experienced by any organism. Every sensation, every urge, every action must transpire in the biological here and now, and there is no alternative—that is the essence of biological experience. And indeed, until quite recently on this planet, that has been the limit of biological experience.
Although an organism has no means to step outside of its biological immediacy, humans have demonstrated that organisms can use the material of biological immediacy to represent something else, to represent that which is not biologically immediate. It is in this way that language serves as a bridge to previously unknown and always unreachable realms: using language, an organism remains within the required confines of its biological immediacy while using something inside that biological immediacy—the material of language—to represent something beyond its biological immediacy.
The material of language can be almost anything—humans began with abstract gestures and vocalizations, and have recently adopted materials that can be touched and more widely seen or heard. What is transformational and important about language is not the material itself but the elements and structure being represented—events of time, space and other non-biological conceptualizations. Although an organism can never directly engage such elements, it can use its belief in the value and accuracy of the language representing such elements to change the course of its own biological immediacy. And thus it is that humans have in large part separated themselves from their evolutionary animal past.
If one wants to understand the origins and structure of language, one does not focus on the material of language, since that material itself is almost completely arbitrary. (And one goes even further afield to focus on mentalizations or brain processes, since mentalizations are little more than the re-creation of the arbitrary materials of language.) If one wants to understand the origins and structure of language, one focuses instead on the non-biological elements being represented, and wonders about their sudden recognition and their peculiar form. After all, this planet passed more than four billion years without any species ever considering time, space or any other non-biologically immediate concept. And humans too, they passed hundreds of thousands of years completely oblivious to anything outside their biological immediacy.
Keep in mind: that which is far removed from biological immediacy is also far removed from normal biological perception.