Researchers asked eight open-weight AI language models 100 verifiable factual questions in English, Russian and Uzbek. The pooled error rate was 3.5% in English, 10.9% in Russian and 15.9% in Uzbek, with the difference statistically significant.

The size of the gap varied by model. One 12-billion-parameter general-purpose model performed reliably across all three languages, while smaller models had Uzbek error rates of 24% to 27%. Models that had been further trained or fine-tuned for Uzbek reduced their error rates to 2% to 8%.