We use language to communicate with others. By communicating, we can exchange our knowledge and views with others. Based on the adage “knowledge multiplies when shared”, when knowledge is shared among people, they can test, build, expand, refine, etc. on it, thereby optimizing and multiplying it, which is further tested, built, expanded, refined, etc. upon sharing with others again, thereby further optimizing and multiplying it, and so on.
Such sharing is responsible for development of the overall intelligence of the mankind, but that is just one of its functions.
In detail: We all know that we use the thought processes to gain and utilize knowledge in the brain. As thoughts work internally in the brain, it uses language to communicate with others in a comprehensive manner.
Even when language helps in communicating with others, that is not what it was originally designed for by the optimizing aspect of natural selection, as explained below.
If you want to call a person out of a huge crowd, you need to know his/her name. Without using a name, it becomes cumbersome and time consuming.
In the same way, we give names to anything we experience in our interactions; may they be physical or mental, so we can recall them later at will.
Recalling them at will enables us to arrange them in meaningful ways, which we do by following the grammar of language we are communicating in.
It helps us plan and manage our ongoing and future interactions in optimized manner.
It is only after we arrange them into language in such a way, that we can use it to communicate with others.
Based on the same, the primary function of language is not communication, but recalling and managing memories to optimize our interactions.
The dual benefits of language are 1) by using it, we can recall memories and contents of our experiences and also project them into future, which enrich our thought processes and provide knowledge by enabling us to contemplate, deliberate, ponder, etc. over them to optimize our interactions and 2) pass on its benefits by directly or indirectly exchanging such knowledge with others in multiple ways, making it the chief contributing factor responsible for the development of human intelligence, only limited by how developed languages are and how they are utilized.
Thoughts and language: Most of our thoughts are without language. E.g., while choosing between red dress and a black dress to wear, you do not convert your choice into language by saying to yourself, “I’ll wear the black dress”. You simply pick up the chosen one. That does not mean that you did not make a decision – Its only that your decision did not use language. On the other hand, when you, e.g., buy a cell phone, you may say to yourself, “It’s better to have a larger display for the price compared to a larger memory, as I’m only going to use it to make phone calls and check emails.”
Language is only needed 1) when one needs to recall something from the past at will, as explained earlier and 2) when there is deliberation to be done, as it requires one or more chains of decisions progressing in a sequential manner, where each decision is based on previous ones in the chain, which can best be done by converting it to language, as language helps recall specific experiences or memories based on its content.
Such revelation also resolves the mystery of why animals and other organisms live only in the present moment. Without language, it is not possible for them to recall memories from their earlier experiences at will to plan and manage their ongoing and future experiences. They are locked up in their present moment, as they can only recall memories from their earlier experiences that are contextually connected to their ongoing interactions.
It is for this reason they cannot think about events that have happened in past at will, nor can they imagine future situations.
Even with such limitations, they exhibit intelligent behaviour, which is either hard-wired in their brains from multiple earlier generations or is limited, as it does not have the boost of intelligence offered by language.
The question is, as language is the chief contributing factor for the intelligence of the mankind, would it still be superior to other species if they also had highly developed language?
Note: This post sufficiently explains the primary function of language and why animals live only in the present moment. For those who want to dig deeper into the other side of language, the step-by-step explanation of how the thought process works, how it is influenced by unconscious thoughts and why, when and how some of the thoughts are converted into language is available in my book Mechanisms of the Mind.