Audio
Each dialogue node contains a Dialogue Sound variable that you can attach your sounds to.
Dialogue Sound Attenuation
You can set a sound attenuation asset on your dialogue's class defaults to make the 3D, 2D or any other effect you wish to have.
See dialogue sound attenuation
Audio missing error
Narrative will display an icon when a node is missing audio. This is a helpful hint to tell the user when they have missed it.
This can be disabled by going to Edit -> Project Settings -> Narrative Dialogues - Editor and unchecking Warn Missing Sound Cues