Tralaleros at SemEval-2026 Task 9: Multilingual Polarization Detection with Transformer-based Models

Adrian Dahl, Bado Völckers, Adam Mierzwa


Abstract
We present a multilingual polarization detection system for SemEval-2026 Task 9 (Subtask 1), covering 22 languages with transformer-based models. We evaluate four strategies: data rebalancing, hyperparameter optimization, model scaling, and ensembling, and show that undersampling harms performance, while larger pretrained models improve results substantially. Our best single model, XLM-RoBERTa Large, achieves a Macro-F1 of 0.7929, with analysis showing complementary strengths across model families (e.g., RemBERT for several Indic languages and mDeBERTa for Semitic/morphologically rich languages). Ensemble gains are marginal, suggesting language-aware routing is more promising than uniform aggregation. We also provide a privacy-preserving Firefox extension that runs local ONNX inference for practical deployment without sending user text to external servers.
Anthology ID:
2026.semeval-1.51
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:
343–353
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.51/
DOI:
Bibkey:
Cite (ACL):
Adrian Dahl, Bado Völckers, and Adam Mierzwa. 2026. Tralaleros at SemEval-2026 Task 9: Multilingual Polarization Detection with Transformer-based Models. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 343–353, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Tralaleros at SemEval-2026 Task 9: Multilingual Polarization Detection with Transformer-based Models (Dahl et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.51.pdf
Supplementarymaterial:
 2026.semeval-1.51.SupplementaryMaterial.zip