TrenTeam at Multilingual Counterspeech Generation: Multilingual Passage Re-Ranking Approaches for Knowledge-Driven Counterspeech Generation Against Hate

Daniel Russo


Abstract
Hate speech (HS) in online spaces poses severe risks, including real-world violence and psychological harm to victims, necessitating effective countermeasures. Counterspeech (CS), which responds to hateful messages with opposing yet non-hostile narratives, offer a promising solution by mitigating HS while upholding free expression. However, the growing volume of HS demands automation, making Natural Language Processing a viable solution for the automatic generation of CS. Recent works have explored knowledge-driven approaches, leveraging external sources to improve the relevance and informativeness of responses. These methods typically involve multi-step pipelines combining retrieval and passage re-ranking modules. While effective, most studies have focused on English, with limited exploration of multilingual contexts. This paper addresses these gaps by proposing a multilingual, knowledge-driven approach to CS generation. We integrate state-of-the-art re-ranking mechanisms into the CS generation pipeline and evaluate them using the MT-CONAN-KN dataset, which includes hate speech, relevant knowledge sentences, and counterspeech in four languages: English, Italian, Spanish, and Basque. Our approach compares reranker-based systems employing multilingual cross-encoders and LLMs to a simpler end-to-end system where the language model directly handles both knowledge selection and CS generation. Results demonstrate that reranker-based systems outperformed end-to-end systems in syntactic and semantic similarity metrics, with LLM-based re-rankers delivering the strongest performance overall. This work is the result of our participation in the Shared Task on Multilingual Counterspeech Generation held at COLING 2025.
Anthology ID:
2025.mcg-1.9
Volume:
Proceedings of the First Workshop on Multilingual Counterspeech Generation
Month:
January
Year:
2025
Address:
Abu Dhabi, UAE
Editors:
Helena Bonaldi, María Estrella Vallecillo-Rodríguez, Irune Zubiaga, Arturo Montejo-Ráez, Aitor Soroa, María Teresa Martín-Valdivia, Marco Guerini, Rodrigo Agerri
Venues:
MCG | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
77–91
Language:
URL:
https://aclanthology.org/2025.mcg-1.9/
DOI:
Bibkey:
Cite (ACL):
Daniel Russo. 2025. TrenTeam at Multilingual Counterspeech Generation: Multilingual Passage Re-Ranking Approaches for Knowledge-Driven Counterspeech Generation Against Hate. In Proceedings of the First Workshop on Multilingual Counterspeech Generation, pages 77–91, Abu Dhabi, UAE. Association for Computational Linguistics.
Cite (Informal):
TrenTeam at Multilingual Counterspeech Generation: Multilingual Passage Re-Ranking Approaches for Knowledge-Driven Counterspeech Generation Against Hate (Russo, MCG 2025)
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PDF:
https://aclanthology.org/2025.mcg-1.9.pdf