Here is a real, unedited line of dialogue from the first draft of my first novel: 'As you know, Marcus, our parents divorced when we were both in middle school, and I think that experience shaped how both of us approach relationships.' A grown woman says this. To her brother. Who was there. Who is also a grown adult and presumably remembers his own childhood. I wrote it with a completely straight face and felt clever, because the reader needed that backstory, and look how efficiently I'd delivered it.
Reader, the reader did not need it delivered like a deposition. I had confused 'information the reader needs' with 'information a character would say,' and that confusion was poisoning every conversation in the book.
The 'as you know, Bob' disease
There's a name for this — 'as you know, Bob' dialogue — where characters narrate facts at each other purely so the audience overhears. Once you can see it you can't unsee it, and I couldn't see it, because I was inside it. So I took my worst scene, a kitchen argument between two estranged siblings, and ran it through Punch Up Flat Dialogue to Sound Like Real People. I used GPT-4o specifically because this is a high-volume, fast-iteration job — I had forty scenes to fix, and GPT-4o is quick and cheap enough that I could run the whole manuscript through without thinking about cost.
The prompt asks for the subtext as a separate field, which forced me to actually name the real fight. I typed: 'They're arguing about who hosts Thanksgiving but it's really about who took care of Mom while she was dying, and which of them gets to feel righteous about it.' The second I wrote that sentence I understood my own scene better than I had in three drafts.
What came back, and the line that gutted me
GPT-4o flagged six lines that existed only to inform, deleted them, and rewrote the exchange so the siblings argued about a turkey and a guest list while the dead mother sat in every silence between them. My original 'as you know' paragraph became, in the rewrite, the sister setting down a coffee mug too hard and saying: 'You weren't there.' Three words. Marcus says, 'I had a job.' She says, 'I know.' And that's the beat. The whole nine-month history of resentment, in 'I know,' because of course she knows, that's exactly the problem.
The 'what changed' notes were the real education. They didn't just rewrite; they taught. Note two said: 'Characters answer the question they wish they'd been asked. When Marcus deflects to his job, he's answering an accusation she didn't technically make, which tells the reader the accusation is real and they both know it.' I've thought about that sentence a hundred times since. It reframed dialogue for me entirely — a line isn't there to transfer information, it's there to show what a person is dodging.
What surprised me most is how much got cut. My instinct as a young writer was always to add — another clarifying line, another beat of explanation, a little stage direction so the reader wouldn't miss the point. The rewrite did the opposite. It deleted six lines outright and replaced two more with silence, and the scene got more powerful as it got shorter. That's a deeply counterintuitive lesson for someone whose whole anxiety is that the reader won't understand. The reader understands. The reader understands faster than you think, and resents being told twice.
The four rules I internalized
- Nobody explains their own backstory to someone who already knows it. If the reader needs it, smuggle it in through conflict, not exposition.
- People answer the question they wish you'd asked, not the one you asked. Deflection is characterization.
- Silence and a too-hard-set mug carry more weight than any line you can write.
- Two people with different vocabularies do not magically converge mid-fight. Let them stay mismatched.
The honest caveat
First time I ran it, the rewrite over-corrected into mumblecore — so naturalistic it became vague, everyone trailing off until I couldn't follow the argument. The fix was the register note. I added 'the sister is a litigator who stays precise even when furious; the brother gets sloppy and loud,' and suddenly the dialogue was naturalistic AND legible, because the precision lived in one character. Use that field. It's the difference between real and just messy.
I ran all forty scenes through it over one long, slightly unhinged weekend. The book is a different animal now — people talk like people, and the backstory arrives in the cracks instead of in lectures. Grab the Punch Up Flat Dialogue to Sound Like Real People prompt on Prompt Dock, feed it your stiffest exchange and the real fight underneath it, and watch your characters stop explaining themselves. Then run the cleaned-up scene through my Check a Character's Voice for Drift Across Scenes prompt to make sure each person still sounds like only themselves.