why do people talk?

Answer 1

To communicate. To express their thoughts. To connect with and share ideas, emotions, experiences with other human beings.

So that one can elicit a positive response from others and feel special, wanted, needed, important. To commiserate with others and laugh at frightening, stressful or just plain silly situations. To dispel imaginary tensions between people that build up in the silence. To facilitate cooperation in work towards a common goal.

Answer 2

Because that's one of the few things that makes us not an animal. Also because we are taught to talk, and everyone else does. You need to be able to talk in order to survive in the human's world. Dogs can't talk, so they are sold for money.