How to Make AI Stop Sounding Like a Robot: Build a Simple Voice File

You've tried it. You asked AI to write a Facebook post and got back something that opens with "Attention business owners!" and mentions "unlocking potential" twice. Technically words, but not your words. So you fixed it by hand, which took longer than writing it yourself, and quietly concluded AI isn't for you.

Here's the thing though: the AI doesn't know you. It's never met you. Asking it to write in your voice without telling it what your voice is — that's like asking a new employee to "just sound like me" on day one. Of course they can't. You haven't told them anything.

The fix is a voice file. One page, about 20 minutes to write, and you'll use it forever. Here's mine — well, the recipe for mine.

What goes in a voice file

Open a blank doc. Four sections.

1. Three things you always say. Not slogans — the actual phrases and habits that come out of your mouth. Do you call customers "folks"? Do you always explain the why before the what? Do you sign off emails with "cheers"? Write down three. If you're stuck, read your last ten sent emails — your voice is sitting right there.

2. Three things you'd never say. This is the powerful one, because AI defaults are made of exactly this stuff. Mine includes "solutions", "game-changer" and anything with more than one exclamation mark. Yours might be "cheap" (if you're premium), "luxury" (if you're not), or industry jargon your customers don't use.

3. Two real examples of you writing. Copy in two things you've actually written that sound like you on a good day — an email a customer replied warmly to, a post that got comments, even a good text message. Real examples teach AI more than any list of adjectives. "Friendly but professional" means nothing; your actual sentences mean everything.

4. How you talk about customers. One or two lines. Who are they, what do you call them, how do you feel about them? "Our customers are time-poor tradies. We talk to them like mates, never down to them. We never call them 'clients'." That kind of thing.

That's it. One page. Here's a condensed made-up example so you can see the shape:

Voice file — Suds & Co Mobile Dog Wash Always: call dogs by name before we mention the owner; plain words ("wash", not "grooming experience"); a bit of gentle humour. Never: "pamper", "fur baby", anything that sounds like a spa brochure, more than one exclamation mark. Example of me: "Hi Jen — Banjo was a legend today, only tried to eat the hose twice. Same time next month?" Customers: busy dog owners who love their dogs but not the hair in the car. Talk to them like a friendly neighbour, not a vet clinic.

How to actually use it

Dead simple. Before you ask AI to write anything, paste the whole file into the chat with this on top:

"Here's my brand voice file. Use it for everything you write in this conversation. Don't mention it, just write this way."

Then ask for what you need. That's the entire trick. If you use the same AI tool regularly, most of them now let you save this permanently — custom instructions, projects, that sort of thing — so you paste it once and it sticks. But pasting at the top of a chat works everywhere, every time, no tech setup required. (If you haven't picked a tool yet, five worth testing this FY27 — with a 10-minute test for each.)

Before and after

I asked for "a short Facebook post about our winter special — $10 off midweek washes".

Without the voice file: "Attention pet parents! Winter is here, and it's the perfect time to pamper your fur baby! For a limited time, enjoy $10 OFF all midweek washes! Don't miss out — book today!"

Four exclamation marks. "Fur baby." A robot in a party hat.

With the voice file: "Winter update: the dogs are muddy, the car seats are suffering, and we can help. $10 off midweek washes through July. Banjo's mum already booked — your move."

Same offer, but it sounds like a person. Specifically, a person you'd trust with your dog.

Three mistakes to dodge

I made all of these so you don't have to.

Writing who you wish you were. If your voice file says "witty and bold" but your actual emails are calm and kind, the AI will write like a stranger. Describe the real you — that's the whole point.

Making it three pages. Longer isn't better. AI follows a tight one-pager far more reliably than an essay, and you're more likely to actually paste in something short. One page, hard limit.

Setting and forgetting. Your voice drifts — mine got noticeably more relaxed once I stopped trying to sound like a "proper" business. Skim the file every few months, swap in a fresher example, cross out anything that no longer sounds like you.

Do it this week

Twenty minutes. Read your sent emails, write the four sections, save it somewhere you can find it (mine's literally called voice-file.doc and lives on my desktop). Then paste it into your next AI chat and watch the robot disappear. Want the fill-in-the-blanks version instead of a blank doc? It's in the brand voice prompt pack.

The AI was never the problem. It just needed the induction you'd give any new starter. And once it has one, it makes every other prompt better too — including the Monday admin ones.