Many animals other than humans live in social groups, and many of those demonstrate complex cooperative behavior, much of which is mediated by communication. In non-human species this communication is described as signal-based. Scientists who conduct field studies of social creatures (and even those who watch television programs about those social creatures) are familiar with the mating and alarm calls of social animals which are examples of this communication. Some of those calls are quite complex; for example in some predator species these signals coordinate behavior among several individuals that comprise a hunting group, and scientists have observed alarms that vary depending on the nature of the threat and communicate a multi-part message. Signal-based communication can even be observed between species, a familiar example is the communication between humans and our companion and work animals.
Among humans, however, communication can be mediated through language which is much more sophisticated than signals or calls, and humans are the only species in which language is widely observed. Some scientists have suggested that the language skills demonstrated by other primates indicate that language is not unique to humans. Critics of that research have pointed out that the language abilities are equivalent to those developed by humans at a very young age (pre-school age children) and those results are observed only after a training period that is far longer is necessary for humans to develop similar abilities. Critics also point out that non-human primate language is not observed in nature.
Linguists have concluded that language-based communication in humans is differentiated from signal-based communication in four ways. First, languages follow grammar or syntax which are the rules followed when communicating in the language. Second, languages have semantics which is what is meant by the messages encoded in the syntax; through shared syntax and semantics spoken words and phrases have common meaning for both the speaker and the hearer. Third, languages allow for humans to create and communicate abstract ideas in a way that signal-based communication cannot. Finally, languages allow syntax, semantics, and abstract ideas to be combined to build and communicate an infinite combination of ideas.
Linguists currently fall into two groups; there are two paradigms guiding their work. One group is guided by the dominant theory that language is a cultural invention and that the language of a culture exerts defining influences on the culture. When taken to the extreme, this theory has been used to draw some racist conclusions that did not stand up to either criticism or evidence. This paradigm fell out of favor for several decades, but in his 2010 book Through the Language Glass: Why the World Looks Different Through Other Languages, linguist Guy Deutscher suggested there exists stronger support for the social construction of language than scholars have been allowing.
The other group, which has been the more influential in recent decades, is guided by the dominant theory that language is a human instinct and that some aspects of it, including grammar, are “hard-wired” into brains. Regardless of which origin linguists conclude is correct (or even if further research supports some other explanation for the origins of human language), the central role of social interaction mediated through language in human development and human nature, and thus on human learning is well-established by multiple lines of evidence.
Deutscher, Guy. 2010. Through the Language Glass: Why the World Looks Different in Other Languages. New York: Metropolitan Books.