During meditation, why is it important to talk to oneself? The basic reason is to detach yourself from all the other thoughts occurring during that time and detaching yourself from the surroundings as well. People, events, situations, happenings and all the incidents that took place, are insignificant during meditation so declutter your mind from all such thoughts and focus on your own self. 

Then give your mind some elevated thoughts to churn upon. Thoughts like you are a child of the Supreme father who is  the mightiest of all, you also have the same innate qualities as God has. You are a great soul.. and so on. These elevated thoughts get imprinted on the active subconscious mind while meditating, and the subconscious mind magically starts to turn them into reality.