ConLID: Supervised Contrastive Learning for Low-Resource Language Identification

Negar Foroutan, Jakhongir Saydaliev, Grace Kim, Antoine Bosselut


Abstract
Language identification (LID) is a critical step in curating multilingual LLM pretraining corpora from web crawls. While many studies on LID model training focus on collecting diverse training data to improve performance, low-resource languages – often limited to single-domain data, such as the Bible – continue to perform poorly. To resolve these class imbalance and bias issues, we propose a novel supervised contrastive learning (SCL) approach to learn domain-invariant representations for low-resource languages. We show that our approach improves LID performance on out-of-domain data for low-resource languages by 3.2 percentage points, while maintaining its performance for the high-resource languages.
Anthology ID:
2026.eacl-long.315
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
6693–6708
Language:
URL:
https://aclanthology.org/2026.eacl-long.315/
DOI:
Bibkey:
Cite (ACL):
Negar Foroutan, Jakhongir Saydaliev, Grace Kim, and Antoine Bosselut. 2026. ConLID: Supervised Contrastive Learning for Low-Resource Language Identification. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 6693–6708, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
ConLID: Supervised Contrastive Learning for Low-Resource Language Identification (Foroutan et al., EACL 2026)
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PDF:
https://aclanthology.org/2026.eacl-long.315.pdf
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