SwanNLP at SemEval-2026 Task 5: An LLM-based Framework for Plausibility Scoring in Narrative Word Sense Disambiguation

Deshan Sumanathilaka, Nicholas Micallef, Julian Hough, Saman Jayasinghe


Abstract
Recent advances in language models have substantially improved Natural Language Understanding (NLU). Although widely used benchmarks suggest that Large Language Models (LLMs) can effectively disambiguate, their practical applicability in real-world narrative contexts remains underexplored.SemEval-2026 Task 5 addresses this gap by introducing a task that predicts the human-perceived plausibility of a word sense within a short story. In this work, we propose an LLM-based framework for plausibility scoring of homonymous word senses in narrative texts using a structured reasoning mechanism. We examine the impact of fine-tuning low-parameter LLMs with diverse reasoning strategies, alongside dynamic few-shot prompting for large-parameter models, on accurate sense identification and plausibility estimation. Our results show that commercial large-parameter LLMs with dynamic few-shot prompting closely replicate human-like plausibility judgments. Furthermore, model ensembling slightly improves performance, better simulating the agreement patterns of five human annotators compared to single-model predictions.
Anthology ID:
2026.semeval-1.109
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:
777–784
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.109/
DOI:
Bibkey:
Cite (ACL):
Deshan Sumanathilaka, Nicholas Micallef, Julian Hough, and Saman Jayasinghe. 2026. SwanNLP at SemEval-2026 Task 5: An LLM-based Framework for Plausibility Scoring in Narrative Word Sense Disambiguation. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 777–784, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
SwanNLP at SemEval-2026 Task 5: An LLM-based Framework for Plausibility Scoring in Narrative Word Sense Disambiguation (Sumanathilaka et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.109.pdf
Supplementarymaterial:
 2026.semeval-1.109.SupplementaryMaterial.zip