A definition of Language

Consider this question - Who is the smartest man in the world?

What is the role of 'who'? What does 'who' do here? There is a "subject" i.e. something we are considering - 'smartest man in the world'. And the word 'who' points to an aspect of the subject, namely, identity. Similarly, we could have had a question like - where is the smartest man in the world? - wherein the word 'where' pointed to the location (aspect) of the subject. So, Wh-words point to aspects (like location, time, identity etc.) of whatever we are considering.

But how many such aspects are there, to anything? Practically, infinite. That doesn't mean we have infinite wh-words, each for each aspect. So we have the mother-wh-word 'WHAT' into which every wh-word can be converted into. For example, 'where is he?' can be converted to 'what is his location?' 'What' is the basic, universal data-procurement operator (wh-word). It is the operator to extract anything that EXISTS. This is because whatever we speak or write falls under 'WHAT is this/that?'

So, 'what' is used when there is a lack of knowledge, in general.

Now, the question is - how do we learn to use words like 'what', 'where', 'when' etc.? Right now, we are talking about the mother word 'what'. So let's ask - how do we learn to use 'what'? MY KNOWLEDGE OF MY STATE OF LACK/ABSENCE OF KNOWLEDGE OF SOMETHING IS TIED TO MY USAGE OF THE WORD 'WHAT'. I have a rough association-rule in my mind as to when there is a scan of my memory which results in lack or absence of knowledge of something, I have to utter a 'what'. 

So, we learn language by associating "states" of mind with words.

Thus, language is a symbol for the self-reflected states of mind.