SIMPLE: A Comparative Study of Prompting and Fine-Tuning for LLM-Based Text Simplification

Zixian Meng, Dongqiang Yang


Abstract
Fine-tuning and prompting are two widely used approaches for adapting large language models to downstream tasks. However, their effectiveness on text simplification remains underexplored. We present SIMPLE, a comprehensive evaluation of large language model-based sentence simplification. We evaluate 12 open-weight large language models across diverse domains, including Wikipedia, medical, scientific, and news texts. In addition to standard evaluation metrics, we conduct a linguistic analysis of simplification outputs at the lexical, syntactic, and discourse levels. Our findings show that: 1) under practical deployment settings, QLoRA fine-tuning of base models performs better on Wikipedia-based simplification, whereas optimized prompting of instruction-tuned models performs better in non-Wikipedia domains; 2) QLoRA-fine-tuned models exhibit a strong alignment with human-written references across target readability levels, while prompted models show limited controllability over output difficulty; and 3) the primary discrepancies between large language model-generated simplifications and human references arise from syntactic restructuring and discourse coherence.
Anthology ID:
2026.emnlp-main.2306
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
52403–52424
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2306/
DOI:
Bibkey:
Cite (ACL):
Zixian Meng and Dongqiang Yang. 2026. SIMPLE: A Comparative Study of Prompting and Fine-Tuning for LLM-Based Text Simplification. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 52403–52424, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SIMPLE: A Comparative Study of Prompting and Fine-Tuning for LLM-Based Text Simplification (Meng & Yang, EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2306.pdf