ThaiPaliBench: Benchmarking Large Language Models on Thai-Script Pali Understanding

Nobpharat Phetsri, Anon Saeoueng, Sarawoot Kongyoung, Waranrach Viriyavit


Abstract
The application of large language models (LLMs) to Pali written in the Thai script remains limited in accuracy due to its low-resource setting, complex grammar, and the absence of standardized evaluation benchmarks. In this paper, we introduce ThaiPaliBench, a comprehensive benchmark dataset designed to systematically evaluate LLM proficiency in Thai-script Pali. Our proposed dataset is an LLM-assisted benchmark derived from the Royal Pali Examination corpus and spans Parian Tham levels 1-9. ThaiPaliBench, comprises multiple-choice and sentence-pair tasks that evaluate grammatical knowledge, reading comprehension, natural language inference, and translation understanding. To verify the effectiveness of our benchmark, we evaluate over 10 model variants across 3 commercial and open-source LLM families, including ChatGPT, Claude, Kimi, Grok, Typhoon, GPT-OSS-120B, ThaiLLM, and SEA-LION. Our experiments show that even the best-performing model, Kimi K2.5 (1T), achieves only 68.3% overall accuracy, with performance dropping substantially on grammatical reasoning and semantic inference tasks. These results highlight the unique challenges posed by Thai-script Pali and confirm that ThaiPaliBench serves as a reliable, linguistically grounded benchmark for evaluating LLM proficiency in this low-resource language. Our proposed dataset is publicly available at: https://github.com/ainrg-llm-dev/ThaiPaliBench
Anthology ID:
2026.findings-emnlp.1278
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
27072–27099
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URL:
https://aclanthology.org/2026.findings-emnlp.1278/
DOI:
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Cite (ACL):
Nobpharat Phetsri, Anon Saeoueng, Sarawoot Kongyoung, and Waranrach Viriyavit. 2026. ThaiPaliBench: Benchmarking Large Language Models on Thai-Script Pali Understanding. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 27072–27099, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ThaiPaliBench: Benchmarking Large Language Models on Thai-Script Pali Understanding (Phetsri et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1278.pdf