Run a paragraph of AI-generated text through a readability checker next to a paragraph a person dashed off in a text message, and a pattern shows up almost every time: the AI version runs longer sentences, more subordinate clauses, and a noticeably higher grade level — even when both are saying roughly the same thing.
I don’t think this is a coincidence of training data. It’s a structural byproduct of how these models are trained and rewarded. Human writing, especially casual writing, is full of sentence fragments, run-on thoughts corrected mid-stream, and abrupt topic changes — the kind of imperfection a language model is statistically discouraged from reproducing, because it’s trained to produce text that reads as complete and well-formed by conventional grammar standards. “Well-formed,” in practice, tends to mean longer: a fully qualified, grammatically complete sentence naturally accumulates more clauses than the clipped way people actually talk.
There’s also a compounding effect from how a lot of AI writing gets used. Marketing copy, business emails, and reports — the categories where AI drafting tools see the heaviest use — already skew toward formal, hedge-everything phrasing before a single AI model gets involved. Feed a model a request to sound “professional” and “thorough,” and it will reliably reach for more words and longer sentences as the default proxy for both.
The practical cost shows up in readability scores. A paragraph that would score at a 9th-grade reading level in a person’s own voice can come back at a 13th- or 14th-grade level after an AI pass — not because the ideas got more complex, but because the sentences got longer and the transitional phrasing got heavier (“in order to,” “it is important to note that,” “with respect to”).
**The fix isn’t avoiding AI tools — it’s editing what they hand you.** A few concrete habits:
– Read the output out loud. Sentences that are hard to say in one breath are hard to read in one pass.
– Break any sentence with more than two commas into two sentences.
– Delete “in order to,” “it is important to note that,” and “with respect to” on sight — they add clause length without adding meaning.
– Run the result through a reading-level checker and compare it to your own unedited first draft. If the AI version scores meaningfully higher, that’s a signal to trim, not a sign the writing improved.
AI drafting can save real time on a blank page. It just isn’t optimizing for brevity unless you specifically ask it to — and even then, treat the output as a first draft, not a final one.
About the author
Kent Williams is the founder and developer of Open Character Counter, a free browser-based tool for tracking character counts, word counts, and readability. He writes about writing constraints, platform limits, and SEO — drawn from building and maintaining tools that help people fit their words into the box.
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