Tooka-SBERT: Lightweight Sentence Embedding models for Persian

Ghazal Zamaninejad, MohammadAli SadraeiJavaheri, Farnaz Aghababaloo, Hamideh Rafiee, Milad Molazadeh Oskuee, AmirMohammad Salehoof


Abstract
We introduce Tooka-SBERT, a family of Persian sentence embedding models designed to enhance semantic understanding for Persian. The models are released in two sizes—Small (123M parameters) and Large (353M parameters)—both built upon the TookaBERT backbone. Tooka-SBERT is pretrained on the Targoman News corpus and fine-tuned using high-quality synthetic Persian sentence pair datasets to improve semantic alignment. We evaluate Tooka-SBERT on PTEB, a Persian adaptation of the MTEB benchmark, where the Large model achieves an average score of 70.54% and the Small model 69.49%, outperforming some strong multilingual baselines. Tooka-SBERT provides a compact and high-performing open-source solution for Persian sentence representation, with efficient inference suitable for both GPU and CPU environments. Our models are publicly available on Hugging Face, and the corresponding benchmark results can be viewed on the PTEB Leaderboard.
Anthology ID:
2025.findings-ijcnlp.147
Volume:
Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Month:
December
Year:
2025
Address:
Mumbai, India
Editors:
Kentaro Inui, Sakriani Sakti, Haofen Wang, Derek F. Wong, Pushpak Bhattacharyya, Biplab Banerjee, Asif Ekbal, Tanmoy Chakraborty, Dhirendra Pratap Singh
Venue:
Findings
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Publisher:
The Asian Federation of Natural Language Processing and The Association for Computational Linguistics
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Pages:
2415–2425
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URL:
https://preview.aclanthology.org/ingest-ijcnlp-aacl/2025.findings-ijcnlp.147/
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Cite (ACL):
Ghazal Zamaninejad, MohammadAli SadraeiJavaheri, Farnaz Aghababaloo, Hamideh Rafiee, Milad Molazadeh Oskuee, and AmirMohammad Salehoof. 2025. Tooka-SBERT: Lightweight Sentence Embedding models for Persian. In Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics, pages 2415–2425, Mumbai, India. The Asian Federation of Natural Language Processing and The Association for Computational Linguistics.
Cite (Informal):
Tooka-SBERT: Lightweight Sentence Embedding models for Persian (Zamaninejad et al., Findings 2025)
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https://preview.aclanthology.org/ingest-ijcnlp-aacl/2025.findings-ijcnlp.147.pdf