Reddit finding: Banning three words makes Qwen models sharper

A Reddit thread in the r/LocalLLaMA group has shown something surprising: If you forbid the Chinese AI model Qwen from using the English words "wait," "maybe" and "perhaps," the model gets better at solving math problems and uses fewer words to reach the answer.

The user tested the Qwen3.5-4B model on 50 math problems from the MATH-500 test set. When the three words were blocked, the model's answers became more accurate, and the answer itself took up 11-19 percent less text than normal.

The background is that AI language models like Qwen often "think out loud" before giving an answer. In that process, the model often uses hesitant words like "wait" or "maybe" to reconsider itself. It sounds like thoughtfulness, but according to the finding it adds nothing to the calculation itself; it just makes the answer longer and more expensive to generate.

The technique is called a logit bias, a small penalty that makes it less likely that the model chooses certain words, without having to retrain the model from scratch. You simply adjust it while it runs.

The discovery from the Reddit thread, which got more than 300 upvotes, has since been backed up by a scientific study from June 2025 titled "Wait, We Don't Need to 'Wait'!". Here, researchers found that AI models' reasoning could be made 27-51 percent shorter across ten different tests without the accuracy getting worse.

For regular users, this means AI models could potentially answer faster and be cheaper to run without sacrificing the quality of the answers. It is still unclear whether AI companies like Alibaba, which is behind Qwen, will build this kind of adjustment into their upcoming models.