Study finds one diacritic changes model output rate 47% → 94%

rayanpal_ · reddit · 2026-08-25

A study reveals a striking phenomenon: adding a single diacritic to a system prompt can shift GPT-4.1's output rate from 47.3% to 94.3%. The experiment, comparing dotted and undotted Hebrew/Arabic prompts, demonstrates the model's extreme sensitivity to minute character differences. The author provides the full protocol and a GitHub link, inviting replication.

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