A philosophical question

Why does man converse? (I am not asking - how come man converses?)

Is just one of these 2 reasons true? 

1) Is conversation just an "intelligent action"? That is, an intellectual activity; a "subset" of intelligence. Man understands himself (his systemic make-up) and that of others of his kind, i.e. the relation of something like "speech" to the mind, and merely uses speech to get his goals served with the help of other humans, via talking to them. 

2) Actions of the members of the human species, living in co-existence, might clash against one's intentions or might harm him, and hence it is a mechanism to "communicate" to the other person to prevent them from doing those actions.

Or is there a bigger scientific reason than the above two ones?