Say That Again, Would You?

Dialog is one of the bedrock necessities in about 99% of all fiction. Plays and screenplays are almost nothing but dialog, and it's not unusual to see whole scenes or entire short stories that are told entirely in dialog (sometimes, without even speech tags to let the reader know who's talking). It's something that seems like it ought to come naturally - after all, everybody talks, right? Yet dialog is a considerable problem for a lot of writers, and a tin ear for dialog has brought more...