Why Perfect Grammar Is a Red Flag (And How to Tell If Something Is Written by AI)

Key Takeaways

• Flawless grammar isn't proof of good writing anymore. Sometimes it's the first indicator that a robot wrote it.

• AI also uses the same few words: "delve," "tapestry," "boundaries," "moreover. Scientists have even documented the increase!

• Human writing is usually a bit of a mess, with fragments, contractions, and sentences beginning with "And" or "But.

• AI detectors like Turnitin and GPTZero help, but they're far from perfect. They've been demonstrated to label incorrect human writing, particularly that of non-native English speakers.

• Sports Illustrated got caught publishing articles under fake, AI-generated author profiles in 2023. The repercussions led to the sacking of its CEO.

• Tools like SirWritesALot's outline generator can help you plan what to write, so you're never tempted to let AI write the actual sentences for you.

Every sentence the same length. All concepts contained in a neat package. No typos, no tangents, no personality in sight. Sound familiar?

Perhaps it was some sort of “About Us” page from a company. Maybe it was a coworker's LinkedIn post that somehow used the word "journey" twice.

That gut feeling that you had while reading it? It's probably right.

For years, we were taught that clean grammar means credible writing. AI turned that on its head. One of the clearest indicators that something wasn't written by a human is that it is "too polished", meaning it's balanced, it has the right words, and it doesn't have any typos.

This guide breaks down exactly how to tell if something is written by AI, using real examples instead of guesswork, so you can spot it in the wild and avoid sounding like a robot yourself.

How to Tell If Something Is Written by AI

Here's the short version: look for what's missing, not just what's there.

Humans write messy, sometimes on purpose and sometimes by accident. We repeat ourselves. We trail off mid-thought. To make a point, we have to use a sentence fragment. Like that one.

AI doesn't really do that. It is based on years of feedback based on being clear, not being unbalanced, not being offensive, and being interesting. So it automatically defaults to even lengths of paragraphs, neat transitions, and sentences that all end neatly. Compare these two lines about the exact same topic:

• AI version: "Coffee is a beverage enjoyed by millions of people worldwide and offers numerous benefits, including increased alertness and improved focus."

• Human version: "Coffee's basically a socially acceptable addiction at this point. And honestly? It works."

Same idea, completely different fingerprint. One kind of reads like an entry in an encyclopedia. The other sound is like someone talking to you.

This isn't to say that AI is incapable of writing, per se, if you ask it to do so. It's that, when it's left at its default settings, it tends to go with the least risky, most middle-ground choice that's available to it.

It's important for content marketers, especially because AI can generate all the content and then polish the grammar after the fact. However, it wasn't grammar that was the key that made readers believe in a brand; it was voice. If you're having trouble with what to write about, but don't want to use AI to actually write the sentences, an outline generator such as SirWritesALot can sketch out a structure based on the existing top pages in the SERP. You still write the paragraphs yourself. You just don't start from a blank page.

The Telltale Signs AI Leaves Behind (Real Examples)

Beyond "it sounds too smooth," there are specific patterns worth watching for.

Some words are used over and over. AI tends to excessively use words like delve, tapestry, boundaries, and realm, and it uses words like moreover and in a manner that is very different from how humans use them. This isn't a hunch. The word delve appeared approximately 400% more in published medical research since the launch of ChatGPT in late 2022. Rather than the doctors and scientists falling in love with that word, it was their AI writing assistants that were in love, and it was written straight to print.

Structure gets too tidy. Three-item lists. All the paragraphs are suspiciously the same length. Sentences that are constructed in the style of "Not only X but also Y”. An ending paragraph that summarizes all of the information. Have you ever seen any of the AI intros that start with the phrase "In today's fast-paced digital landscape (or world)?” It can't all be a coincidence. It's a statistical default, not a stylistic choice.

Sometimes the evidence is embarrassingly obvious. Sports Illustrated was even caught in late 2023 publishing product review articles with fabricated author names, complete with AI-generated headshots of the sport. Readers were impressed by how the “writers” had no presence elsewhere in the cyber world. The consequences were quite real; the parent company's CEO was ousted in weeks.

Academic publishing has its own version of this. Since then, dozens of peer-reviewed papers have been catalogued where someone accidentally didn't delete this phrase before submitting: As an AI language model, I... A little mis-typing, a rather enormous signature.

How to Make Your Writing Sound More Human

If you're trying to avoid sounding like a robot — or fixing content that already does — these habits help:

• Break a grammar rule on purpose. Start a sentence with "And" or "But." It's not lazy. It's how people actually talk.

• Use contractions, always. "It's" and "you're," not "it is" and "you are."

• Let a little opinion in. A mild complaint, a joke, an "honestly, this part's overrated" moment.

• Vary your sentence length on purpose. Short one. Then a longer one that stretches out a bit before landing somewhere specific.

• Get specific. A real number, a real place, a real brand name. AI tends to stay vague because it wasn't actually there, and you were.

• Cut the fancy AI vocabulary. Swap "utilize" for "use," "leverage" for "use" (yes, again), and "delve into" for "look at."

• Read it out loud. If you wouldn't say it to a coworker over coffee, rewrite it.

None of this means AI can't help you write. It just means the final pass — the one with your actual voice in it — should be yours.

Are AI Detectors Actually Reliable?

There are tools such as Turnitin, GPTZero, Originality.ai and Copyleaks, which all claim to detect AI-generated content. They can be of real assistance. But they have nothing to do with a lie detector test, and the idea of using them as such can create real issues.

A study cited by Stanford published in the Patterns journal revealed that AI detectors flagged over half of the essays written by non-native English speakers as AI-generated, which was probably due to the fact that simpler sentences can statistically look like AI-generated writing. That's a serious false-positive problem, not a minor glitch. Since then, some universities have either reduced or even disabled the detection of AI.

The accuracy claims in the official detector ads even vary in this case when the writing is slightly modified or runs against writing that was published before ChatGPT.

So treat detection tools as one useful signal, not a verdict. Take them against the checks for humans mentioned above: voice, specific information, a little imperfection. Those are much harder to fake.

Conclusion

Perfect grammar used to be the goal. Now, often this is the tell-tale sign. There's no foolproof way to identify AI writing — or to avoid writing AI-style — other than by using a grammar checklist. It's whether an actual person seems to be behind the words: an opinion, a rhythm, a fragment that breaks the pattern on purpose.

When you're looking to create a brand and have your content sound like you rather than someone else's AI-generated blog post, this isn't a grammar issue; it's a voice problem. SirWritesALot's brand voice tool reads your own content to create a profile of what your brand actually sounds like, regardless of whether it is written by AI or not, so that each piece of content is checked against your voice — not the general tone that all AI models will default to.

FAQs

Can AI detectors be wrong?

Yes, regularly. They've been shown to correctly identify human writing as AI-generated at significantly high rates, particularly by non-native speakers of English. Treat a detector score as a hint, not a final answer.

Why does AI use words like "delve" so often?

It's really about the construction and training of these AI tools. Scientists found that actual, sharp increases in the use of the term in published texts immediately followed ChatGPT's release.

Is perfect grammar always a sign of AI?

Not on its own. Many people can write clearly. The authentic signal is perfect grammar and no personality, details, or rhythm.

Can I make AI-generated text sound more human?

To a point. Using contractions and fragments, specific details, and opinion really helps. But writing your own sentences from a solid outline will always sound more like you than editing AI text after the fact.

Won't breaking grammar rules hurt my SEO or make me look unprofessional?

No. Search engines reward content that's genuinely helpful and clearly written by someone with real experience, not content that follows every textbook grammar rule. If you put in a well-placed fragment or a sentence beginning with "But", and the remainder of the fragment or sentence demonstrates that you possess knowledge of the topic, it will sound confident, not careless.