What is the purpose of dialogue in a narrative essay?

The purpose of dialogue in a narrative essay is to give your characters another type of movement.

Explanation:

When you use only actions in a story, it is hard to understand the characters, we don't know what is being said through only actions, and by making them speak, we do. It is always good to make them talk because though "actions speak louder than words" we don; 't know what action is without those words.