Ambirig at SemEval-2026 Task 5: Distributional Ordinal Modelling for Ambiguous Word Senses in Narrative Contexts

Soumyajit Roy


Abstract
Word Sense Disambiguation (WSD) has traditionally been framed as selecting a single correct sense given context. However, natural language understanding by humans often involves ambiguity, underspecification, and graded plausibility judgments rather than categorical decisions. SemEval-2026 Task 5 explicitly targets this gap by requiring systems to predict human-perceived plausibility scores for word senses in short narratives. In this paper, we present a systematic empirical study of modelling plausibility as an ordinal distribution prediction problem. We hypothesise that standard classification objectives fail to capture the ordinal nature of human uncertainty in this domain. While we experimented with complex auxiliary tasks, including Siamese networks, Task-Adaptive Pretraining (TAPT), and transfer learning from Natural Language Inference (NLI), our results show these approaches fail in low-resource settings. Instead, we propose a streamlined architecture based on DeBERTa-v3-base utilising a GlossBERT-style Cross-Encoder optimised with Earth Mover’s Distance (EMD) loss. By modeling the problem as ordinal regression over a probability distribution and enriching inputs with prototypical examples, our system achieves an accuracy of 73% and Spearman correlation of 0.593, establishing a robust baseline that outperforms complex parameter-heavy approaches.
Anthology ID:
2026.semeval-1.84
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:
585–591
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.84/
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Cite (ACL):
Soumyajit Roy. 2026. Ambirig at SemEval-2026 Task 5: Distributional Ordinal Modelling for Ambiguous Word Senses in Narrative Contexts. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 585–591, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Ambirig at SemEval-2026 Task 5: Distributional Ordinal Modelling for Ambiguous Word Senses in Narrative Contexts (Roy, SemEval 2026)
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https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.84.pdf