Team HausaNLP at SemEval-2026 Task 9: Tackling Class Imbalance in Low-Resource Hausa Polarization Detection

Faisal Adam, Sani Aji, Lukman Aliyu, Abdulhamid Abubakar


Abstract
This paper describes our submission toSemEval-2026 Task 9, Subtask 2 (Hausa). Thetask involves identifying specific categories ofpolarization (Political, Religious, Ethnic, etc.)in Hausa social media comments. The datasetpresented significant challenges, primarily extreme class imbalance and the low-resourcenature of the language. Our system uses a pretrained multilingual transformer (Afro-XLMRLarge) fine-tuned with Weighted Binary CrossEntropy loss and dynamic undersampling (1:3ratio) to mitigate the scarcity of polarized examples. On the official test set, our systemachieved an official Macro-F1 score of 0.2346and a Micro-F1 score of 0.2581. Our model isrecall-oriented (Micro-Recall: 0.6166), demonstrating strong capability in detecting polarization, though precision remains a challenge(0.1632). We achieved our best per-class performance in the Political domain (F1: 0.48).
Anthology ID:
2026.semeval-1.8
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
54–58
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URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.8/
DOI:
Bibkey:
Cite (ACL):
Faisal Adam, Sani Aji, Lukman Aliyu, and Abdulhamid Abubakar. 2026. Team HausaNLP at SemEval-2026 Task 9: Tackling Class Imbalance in Low-Resource Hausa Polarization Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 54–58, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Team HausaNLP at SemEval-2026 Task 9: Tackling Class Imbalance in Low-Resource Hausa Polarization Detection (Adam et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.8.pdf
Supplementarymaterial:
 2026.semeval-1.8.SupplementaryMaterial.txt