Evolution and essence of language itself is too comprehensive and too complicated because the term language we use includes too many things, aspects each one of which is being constantly researched and revealed. There seems to be great pearls of logic behind every aspect of every language be it etymology, be it punctuation, be it semantics, be it the syntax , be it the logic for existence of many parts of speech like prepositions in some languages or the lack some parts of speech in some language etc.
Every language has evolved imbued with beauty and utility with marvelous manipulations to make meanings conveyable and meaningful communication.
Language in my opinion has been the most important tool in the growth and development of human evolution in all aspects.
However, it still remains a great puzzle with many of its interesting nuances well explained by great scholars, linguists,scientists, attempted to be studied by many psychologists and neurologists but awaiting a very convincing scientific explanation in terms of evolutionary biology or perhaps it could as Dr.V.S. Ramachandran himself says somewhere, "I’m arguing that what happened is more like your jaw bones: there are different adaptations which evolved for different purposes. For example, bones of the ear that evolved for amplifying sound were exapted from reptilian jaw bones used for chewing. There is a fortuitous emergence of different sets of neurosystems that evolved for completely unrelated reasons—and the equally fortuitous interactions between them resulted in early language, which then became an elaborate system. So, it’s not wrong to say that there was natural selection. But there were multiple exaptations with fortuitous interactions which resulted in language.".
If existence of biological vocal chord alone were to be credited with the ability to come out with nuanced sound structures to explain and express , then many other species would score over humans. I am on an interesting journey learning about the creation, uses and multiple manifestation of many languages reading the works of many linguists of different languages. The beauty is the very process and purpose of many aspects of any language and absence of certain aspects all reveal great logic and love for human interactions by enhancing human communications.