Using AI to Fix Your Grammar? How to Make Sure It Doesn't Change Your Meaning
Here's the TL;DR:
Tell the AI to fix grammar only and to flag unclear sentences instead of rewriting them.
Work one paragraph at a time and keep your original.
Compare the two versions yourself, because the tool's list of changes may be incomplete.
When in doubt, involve a human! We can help.
When using AI to fix your grammar, it can change what you’re saying and what you mean, and it won't always tell you.
I was working with a client recently who was preparing for a presentation. She had written her script and then, like many academics, asked a generative AI tool to correct the grammar. But as she read through the script afterward, she realized that some of the information was no longer accurate. So, while the grammar was correct, the information was wrong.
This post doesn’t tell you to avoid using generative AI. It helps you avoid mistakes when using generative AI.
Why Does AI Change Your Meaning When It Fixes Grammar?
Grammar correction is not meaning-neutral. When you write a sentence that is unclear or could be read two ways, a good human editor will stop and ask, "Did you mean X or Y?" AI usually just decides. It picks the reading that seems most likely, writes it in perfect English, and moves on. It doesn't tell you a choice was made at all, much less why it made the choice it did.
If English is an additional language for you, there's a second problem: polished English looks correct. When the revised sentence sounds more fluent than what you wrote, it's natural to trust it more than your own draft. But remember, in science and healthcare, our language must be precise. Here are some examples of the kinds of changes to watch for. (These are illustrations I created, not my client's actual sentences.)
What you meant | What a "correction" might give you | What changed |
Fiber intake was associated with lower blood pressure. | Fiber intake lowered blood pressure. | An association became a cause. |
This approach may reduce symptoms. | This approach reduces symptoms. | The hedge disappeared. |
10.3% of participants reported side effects. | Few participants reported side effects. | A number became a judgment. In some studies, 10.3% is unacceptably high. |
None of these sentences has a grammar mistake, but all of them could get you a hard question from the audience.
Before You Paste: Set the Rules
Most people type something like "fix my grammar" or "improve this". That gives your AI tool a lot of freedom, and it will use it. You need to be specific about what it is and is not allowed to do. Steal this prompt to fix your grammar without changing your meaning:
Correct grammar, spelling, and punctuation only. Do not rephrase, shorten, or change word choice unless it is a grammatical error. If a sentence is unclear or could mean more than one thing, do not fix it. Flag it and ask me what I meant. After the corrected text, list every change you made and why.The most important instruction is the one about unclear sentences. It forces the tool to ask a question before making a decision, which is exactly what a good editor would do. If you take only one thing away from this post, take this: the prompt reduces the risk of having AI change your meaning, but it doesn't remove it. In fact, AI might not list all of the changes for you, despite your instructions (more on this below!). Understand that there is no magic prompt, which is why the next two steps are a critical part of your process.
While You Work: Keep It Small
Paste one paragraph or one slide's worth of script at a time. It's tempting to paste the whole presentation, but changes are much easier to spot in short pieces. The AI tool is also less likely to start "improving" things you didn't ask about.
Keep your original. Save your draft before you start, so you always have something to compare against. You can't check what changed if the original is gone.
After: Check the Work Yourself
While you asked your AI tool to report every change, the list is the tool's summary of what it did. What surprised me is learning that the list is not guaranteed to include everything. So read the list, and then check for yourself.
DO THIS: Check for changes by running an independent comparison. Paste your original and the revised version into Word's Compare feature or any free text comparison tool. It will show you every difference, whether the AI mentioned it or not.
DO THIS: Check the high-risk words first. If you're short on time, look at these:
Numbers and units
Hedges (may, might, suggests, likely)
Cause-and-effect verbs (led to, caused, resulted in)
Negatives (not, no, without)
Quantity words (few, a few, most, some)
DO THIS: Translate it back. Take the revised sentence and translate it into your first language in your head. If it says something different from what you intended, the meaning changed.
DO THIS: Read it aloud. For each sentence, ask yourself: "Would I say this? Could I defend it if someone asked me a question about it?" If the answer is no, it's not your sentence anymore. Now you’re using AI to generate your text rather than edit it.
Ask Yourself: Are You Still the Author?
AI can refine your sentence, but only you know what you meant. Whether the help comes from a tool or a person, fixing the language without understanding the content is risky. I wrote about that in my post on the difference between language editing and scientific editing.
So, use the tool if it helps you. Just set the rules, work in small pieces, and check the result yourself. When you stand up to present, every sentence should still be yours.
Need help preparing a presentation or checking that your English says what you mean? Book an appointment with us: www.absolutelyenglish.com/book-online
A note on how this post was written: I used an AI assistant (Claude) to brainstorm the topics included in this post and for tips on getting better results from AI. Super meta! And yes, I checked its work.
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