Dialogue is typically a conversation between two or more people in a narrative work. As a literary technique, dialogue serves several purposes. It can advance the plot, reveal a character's thoughts or feelings, or show how characters react in the moment.
What is the purpose of dialogue?
Dialogue is your character's reaction to other characters, and the purpose of dialogue is communication between characters.
What is the effect of dialogue?
Conversation between characters brings stories to life. Dialogue breaks up blocks of text and allows writers to change the pace of their narrative. Well-written dialogue informs readers about the character of the people speaking it, and knowing how to use dialogue in a story allows the writer to progress the narrative.