“Dialogue should simply be a sound among other sounds, just something that comes out of the mouths of people whose eyes tell the story in visual terms.”

Alfred Hitchcock

This is excellent advice for a visual medium, like film. In writing, how do we accomplish the same affect? Communication is 90% non-verbal. When speaking, what actions of your characters tell how they feel, their level of interest, whether they are honest? Dialogue tags are much more telling when they are more than “he said or “she said” but delve into the characters’ feelings by showing us a glimpse inside.