How to Keep Your Own Voice

Why everything ends up sounding the same

This is measured, not an impression. In an experiment with 293 writers and 600 evaluators, the stories written with AI ideas were individually more inventive — 6.7 percent more novel, 6.4 percent more useful — but measurably more similar to each other. Better one by one, greyer together.

The largest study ran on more than 880,000 texts, across seven datasets and three different models. The result: machine "polishing" cut the spread of writing complexity by 21 to 50 percent, and erased the traces a reader would use to infer the author's age, gender or worldview. In another experiment with 118 participants, Indian writers shifted to Western composition habits under the influence of suggestions — not only what they wrote changed, but how.

The reason is simple. The model writes toward the average of its training data. If you do not say what your voice sounds like, the default for "good writing" becomes that average — and the average has no voice. A style sheet is not decoration; it is the only input that overrides this.

The five elements of a style sheet

Five things are worth writing down. With fewer, the model slides back to the average; with more, it starts ignoring your instruction altogether.

• Sentence length and rhythm. Not a mood word but a number: "most of my sentences run 8 to 18 words, and every paragraph has at least one short one." This is the single element a model can follow exactly, and on its own it carries half of what makes text recognisable.
• Vocabulary and register. How formal you are, whether you use jargon without explaining it, how direct you get. Give five words you use often and five you never use.
• The banned list. The strongest single element. "Never open a paragraph with a general scene-setter", "never write crucial", "never close with a summary sentence." Models keep concrete prohibitions; they do not keep general requests.
• Structural habit. How you open — with a question, a claim, an example? Bullets or prose? Is there a closing lesson, or do you simply stop?
• Stance. Whether you state an opinion, whether you own the first person, whether you recommend or merely list options. A model is cautious and impersonal by default, more so than most people — you have to ask for the opposite.

How to work out your own

You do not need self-knowledge for this, just three of your own texts and twenty minutes.

1. Pick three pieces you are proud of. Preferably from the same genre as the thing you are about to write. A mixed selection produces an average, and the average is exactly what we are working against.
2. Count the sentences. In the first two paragraphs, measure the longest and the shortest sentence. Those two numbers become your rhythm rule.
3. List your recurring turns of phrase. Whatever you wrote three times is yours. Whatever you never wrote once belongs on the banned list.
4. Ask the model to describe your style. Give it the three texts and ask for a style description. Keep what you recognise; delete the flattering generalities.

A finished style sheet you can edit

Replace the parts in square brackets with your own. This block goes into the system instruction or the project description — not at the top of every single prompt.

STYLE SHEET — [your name / brand]

Rhythm: most sentences run [8-18] words. Every paragraph contains at least
one sentence [shorter than six words]. At most [four] sentences per paragraph.

Register: [direct, informal, never matey]. I use jargon [without explanation
when the term is in the glossary].

Words I use often: [five words]. Words I never use: [five words].

Never:
- open a paragraph with a general scene-setter
- use any of these: [crucial, comprehensive, in today's world, it is important to note]
- close with a summary paragraph that repeats what is above
- put a three-item list in every paragraph

Structure: [I open with a claim, not a question]. [Example within the first third].
[The close is one concrete next step, not a summary.]

Stance: [I state my opinion and own the first person].
[When something does not work I say so, and say why.]

Where to put it so you stop repeating yourself

If you paste it at the start of every conversation, you will stop within two weeks. There are three more durable places, each at a different scale.

• The global setting. Account-level "custom instructions" apply to every conversation. Rhythm and the banned list belong here — whatever is always true of you.
• Project or workspace instructions. If the voice differs by client or brand, this is the place, together with the reference texts. It is the style-shaped version of what a prompt library does for prompts.
• A named style. Several assistants let you build a style from your own samples and save it under a name. This comes closest to what you actually want, and training on your past writing covers it in full.

How to check that it works

A style sheet is judged by a twenty-minute test, not by how it feels.

• Have the same thing written twice. Once with the style sheet, once without. If you cannot see a difference, the sheet is too general — sharpen the banned list.
• Show it to someone who knows you. Give a colleague both versions unlabelled. If they cannot tell which one is yours, it is not finished.
• Look at what it ignored. A model will typically disregard two or three of your rules. Rewrite those to be concrete — "be direct" is not a rule, "never write crucial" is.

What a style sheet does not fix

A model can learn the surface features — sentence length, word choice, your favourite constructions. It cannot learn the judgement. Measurements show style imitation works in structured, factual genres: on journalistic text, author identification runs at 86 to 93 percent accuracy, while on personal, informal writing it collapses to 16 to 21 percent. In other words, the more something is yours, the less well it transfers.

What follows is that a style sheet makes the rewrite cheaper, not unnecessary. Raw machine text stays recognisable, and the patterns that give it away are listed in the telltale signs for editing. The job of a style sheet is to reduce the rewriting from the whole text to about a quarter of the paragraphs.

What to take away

Your voice is not a matter of style but of input. If you do not supply it, the model writes the average — and measurably flattens whatever you add on top. Write down the five elements — rhythm, register, banned list, structure, stance — put them somewhere durable, and once a month check which rule is being ignored. The banned list does half the work.