Why and How Did Language Evolve?

"Yes, they say they understand, but how do I know they understand? Because words are inert. They are just a symbol. They are dead (movie Waking Life 中) ". When I first heard this line, to me who have been told that language is an absolute or a crucial tools in our life, it was very interesting perspective, and interested me in language. Is language really just a symbol? Is it right to say language is dead? If that's true, why the language even created at the first stage? So now, I am going to elaborate why and how did our language evolve, mainly based on what I've learnt.

Before talk about the topic, what is Language? The dictionary definition of language is a system of communication which consists of a set of sounds and written symbols which are used by the people of a particular country or region for talking or writing, or an action of transfer one's thoughts and feelings to others. (Collins Cobuild Advanced Learner's English Dictionary 6th Edition) A broad concept of language involves the sounds of animals, but in a narrow idea it means the one only possessed by Humans. 'Human language' broadly includes body movement, gesturing, facial expression, and signals. However in a narrow concept, it refers to the vocal language that is spoken through mouth and understood by hearing through ears. Then, why human needed the language?

There are several hypotheses explaining why human started to develop the language as what it is today. First one is the Social Contract hypothesis. According to this hypothesis, human used language to express "who owes what to whom". For instance, in hunting society male needed to inform others this lady is his wife and these people are his family when he leave home for a long time to hunt, so that he can protect his own property. Next, there is Parenting hypothesis. This insists that language have been developed to express approval or rejection to offspring. Furthermore, other opinion about why people started use language is to 'watch' the social network that had been suddenly too complicated and huge. For example, who cheated who, who is trustworthy, who can be alliance, which alliance is about to break and so on. This called the Social Grooming or Gossiping hypothesis. Other hypothesis is Sexual hypothesis, which argues that male tried to attract female by language. As a result, male adopted lower pitch, strong skills of story telling and sweet-talking, and other self-enhancing behaviors. Some believe that this is reason why there are more male poets, novelists and artists.

These four hypotheses are the one mentioned in lecture. However I would like to add one more function of language, to get rid of loneliness. I've heard from somewhere that 'creation' is made from incompleteness, or frustration and endeavor. I think it's same for the language. It is a creation of desire to communicate with others, overcoming the isolation. I think the language is an engagement