How to Write AI Video Scripts That Don't Sound Like AI

Here's the uncomfortable truth about AI video: viewers rarely clock the avatar first. They clock the script. A synthetic face reading natural words passes on a social feed; a real face reading synthetic words doesn't. We've produced enough avatar video through HeyGen and ElevenLabs to know where the uncanny valley actually lives — and it's in the writing.

These are the seven rules we apply to every script before it goes anywhere near an avatar.

1. Draft it spoken, not written

The biggest tell is prose that was written for the eye. Written English tolerates long clauses, semicolons, and words like "utilize." Spoken English doesn't. Our fix: draft by dictating, or tell your AI assistant explicitly — "write this as spoken language for a talking-head video, short sentences, contractions, no subordinate clauses." The difference in output is immediate.

2. One idea per sentence

Avatars don't breathe, pause, or raise an eyebrow to carry you through a complex sentence. Every sentence gets one idea. If you spot an "and" joining two thoughts, split it. This single edit does more for naturalness than any voice setting.

3. Front-load the hook — then cut your intro anyway

Whatever your first sentence is, it's probably a warm-up. Delete it and see if the video gets better. (It almost always does.) The first three seconds decide whether a clip lives or dies, and AI tools will happily render your throat-clearing in perfect 1080p.

4. Write pronunciation into the script

Names, jargon and Dutch words trip every voice engine. Don't fight the engine — feed it phonetics: "Funnelytics" becomes "funnel-IT-icks" in the script, then you fix the caption afterward. ElevenLabs handles this better than most, but every tool needs help with the words that matter most to you — which are usually your own product names.

5. Break the rhythm on purpose

AI narration fails by being too even. Real speakers speed up, slow down, and drop in two-word sentences. Like this. Write those in deliberately: a short punch after two long sentences resets the listener's attention and disguises the metronome underneath.

6. Read it aloud before you render

The cheapest quality gate in this whole workflow: read the script out loud, once, with a timer. Anywhere you stumble, the avatar will stumble more gracefully but less forgivably. And the timer matters because credits are money — every AI video tool bills by the minute, and a script that's 20% flab costs 20% more to render, forever.

7. Keep a voice file

Every time a phrasing works — a way you open, a way you land a point — save it to a running document and paste it into your AI assistant's context before the next script. After ten videos you have something no generic tool has: your voice, transferable. This is also the foundation for the whole one-recording-into-a-month-of-content workflow, where a single well-written script fans out into clips, posts and translations.

The test that matters

Play your rendered video to someone without context. If their first comment is about what you said, the script passed. If it's about how it sounded, go back to rule one.

Scripts are the part of AI video nobody sells you, because there's no subscription for it. The tools are compared honestly in our field-tested AI video roundup — but whichever one you pick, the writing above is what decides whether anyone watches past second three.