Conversations take many forms, but they generally hinge on 3 variables: complexity, intensity, and importance/value.
Now we’re getting into more straightforward aspects of dialogue: intentions, goals, and perspective/opinion.
Stories are driven by conflict, and dialogue is no different. When writing a piece of dialogue, recognize what conflicts exist, and what their underlying cause(s) are. For example, here are 4 common source of conflict in dialogue:
Dialogue, along with prose and description, represent the 3 aspects of scene writing. Characters are either observing, taking action, or talking (sometimes to themselves). Among the 3, dialogue is unique in that it grants every character a voice of their own.
On the small scale, clarity is the meaning of the words the story uses; understanding the rules of grammar, as well as carefully weighing the merits of poetic language and figures of speech (simile, metaphor, analogy, etc.) It’s ensuring audiences have the necessary information to understand “why”; whether it’s why Harry Potter is famous, why he was kept out of the magical world, or why some characters adore Harry while others despise him. Carefully managing “what audiences learn” and “when they learn” is a critical component of good storytelling. (See 107-02 Background Information)