How can I get an AI to stop writing in that stiff, overly formal tone?

You fix stiff AI writing by giving it a specific voice to mimic, not just telling it to 'be casual.' The core problem is that AI models default to a bland, helpful-assistant tone because they're trained to be safe and universally understandable. Telling it to 'sound more human' is too vague. Instead, you need to show it what you mean. I've found the most reliable method is to paste a short sample of your own writing into the prompt and say, 'Rewrite the following text in this exact style.' The AI will analyze your sentence length, word choice, and rhythm. For example, if your writing uses short, punchy sentences and contractions like 'don't' instead of 'do not,' the AI will mirror that. Another trick is to give it a persona with clear vocal traits. A prompt like 'You are a skeptical but friendly coffee shop owner explaining this' will produce wildly different results than 'You are a corporate consultant.' The persona gives the AI a box of mannerisms to play in. A common mistake is just adding words like 'conversational' to your prompt. That's like telling a chef to make food 'tastier'—it's a direction, not a recipe. For a deeper dive, see our guide on fixing AI writing that sounds too formal. **Related**: Why does all AI writing sound the same? | What's the best prompt to make AI sound like me?