Today’s read pages 180-189, section 7 of chapter On Writing.
Dialogue, it gives your cast their voices and is crucial to defining characters. What people are saying often conveys their character in ways of which they are unaware.
Character can be conveyed more vividly through speech. A cardinal rule of good fiction is never tell us anything you can show us. Good dialogue is a delight, bad dialogue is deadly. A writer can improve in respect to dialogue, but a man must know his limitations.
Dialogue is a skill best learned by people who enjoy talking and listening to others…especially listening. The key to writing good dialogue is honesty. It’s important to tell the truth. It must ring true on the page and in the ear. To ring true you must talk yourself and even more importantly listen.
Fearsome Beard 
Writing dialogue is more of a challenge than mere description.