Joshualee2 at SemEval-2026 Task 9: Cross-Lingual Transformer-Based Polarization Detection

Joshua Lee


Abstract
This paper describes our system for POLAR Subtask 1 on multilingual polarization detection. The task involves binary sequence classification over 22 languages, where the model aims to predict whether a given text exhibits polarized discourse. To deal with the multilingual and resource-imbalanced nature of the dataset, we fine-tune the XLM-R, a pre-trained multilingual transformer encoder, using a language-aware sampling strategy that combines all available training data into a unified multilingual corpus. Our system achieves an overall macro-F1 of 0.781 and an average accuracy of 0.823 on the official test set. Results show strong performance in low-resource languages, though some discrepancies indicate remaining class imbalance.
Anthology ID:
2026.semeval-1.347
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:
2760–2764
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.347/
DOI:
Bibkey:
Cite (ACL):
Joshua Lee. 2026. Joshualee2 at SemEval-2026 Task 9: Cross-Lingual Transformer-Based Polarization Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2760–2764, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Joshualee2 at SemEval-2026 Task 9: Cross-Lingual Transformer-Based Polarization Detection (Lee, SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.347.pdf