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OasisSimp: An Open-source Asian-English Sentence Simplification Dataset

Summary

Automatic sentence simplification rewrites text so it is easier to read without changing its content. Research has focused mostly on English and a few other well-resourced languages, and many Asian languages have no parallel complex–simple data. OasisSimp partly fills this gap with an openly released, human-built corpus for English, Sinhala, Tamil, Thai and Pashto.

For each language, the authors drew source sentences from public material such as Wikipedia, news and government documents. They filtered these automatically, adding language-specific rules, and then manually selected the complex sentences. Trained annotators rewrote them under shared guidelines requiring that meaning, fluency and grammaticality be kept.

The corpus also serves as a benchmark. Eight open-weight multilingual LLMs were prompted in zero- and few-shot modes and scored with SARI and BERTScore, with BLEU reported in the appendix. Results reveal a marked quality gap between high-resource and low-resource languages, and no single model is best everywhere. The release offers the first simplification data for Thai, Tamil and Pashto and a challenging test bed for future work.

Key points

  • Five languages with very different resource levels (English 5; Thai and Tamil 3; Sinhala and Pashto 2 on the Joshi et al. scale) and four script types: Latin, Thai, Brahmi-derived and Arabic-derived.
  • Before this work, the only Sinhala resource was SiTSE (1,000 sentences, 3,000 pairs), and no simplification datasets existed for Thai, Tamil or Pashto.
  • Eight models were benchmarked: Aya, Cmd-R, DeepSeek, EuroLLM, Gemma, LLaMA, Mistral and Qwen. Each was tested with 0-, 1- and 5-shot prompting, following the approach of Kew et al. (2023).
  • Appendix BLEU scores (best results):
    • English: EuroLLM, about 23.
    • Sinhala: Gemma, 31.82 at 5-shot; EuroLLM drops to 0.00 there.
    • Tamil: Gemma, 36.71 at 5-shot.
    • Thai: LLaMA, 20.36 at 5-shot.
    • Pashto: Cmd-R, 38.49 at 5-shot.
  • The dataset is available at OasisSimpDataset.github.io.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

Fields: Linguistics & languages · Machine translation

Cite

The paper itself, not this page. BibTeX from the library's record of the work. DOI 10.63317/4ws5ja7xyadd

@inproceedings{liu2026oasissimp,
  title = {{OasisSimp: An Open-source Asian-English Sentence Simplification Dataset}},
  author = {Liu, Hannah and Tian, Murphy and Ali, Iqra and Gao, Haonan and Wu, Qiaoyiwen and Yang, Blair and Thayasivam, Uthayasanker and Lee, Annie En-Shiun and Nakwijit, Pakawat and Ranathunga, Surangika and Shekhar, Ravi},
  booktitle = {Proceedings of the Fifteenth Language Resources and Evaluation Conference},
  year = {2026},
  doi = {10.63317/4ws5ja7xyadd},
  url = {https://doi.org/10.63317/4ws5ja7xyadd}
}

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