PolyFrame at MWE-2026 AdMIRe 2: When Words Are Not Enough: Multimodal Idiom Disambiguation

Nina Hosseini-Kivanani


Abstract
Multimodal models struggle with idiomatic expressions due to their non-compositional meanings, a challenge amplified in multilingual settings. We introduced PolyFrame, our system for the MWE-2026 AdMIRe 2 shared task on multimodal idiom disambiguation, featuring a unified pipeline for both image+text ranking (Subtask A) and text-only caption ranking (Subtask B). All model variants retain frozen CLIP-style vision–language encoders and the multilingual BGE M3 encoder, training only lightweight modules: a logistic regression and LLM-based sentence-type predictor, idiom synonym substitution, distractor-aware scoring, and Borda rank fusion. Starting from a CLIP baseline (26.7% Top-1 on English dev, 6.7% on English test), adding idiom-aware paraphrasing and explicit sentence-type classification increased performance to 60.0% Top-1 on English, and 60.0% Top-1 (0.822 NDCG@5) in zero-shot transfer to Portuguese. On the multilingual blind test, our systems achieved average Top-1/NDCG scores of 0.35/0.73 for Subtask A and 0.32/0.71 for Subtask B across 15 languages. Ablation results highlight idiom-aware rewriting as the main contributor to performance, while sentence-type prediction and multimodal fusion enhance robustness. These findings suggest that effective idiom disambiguation is feasible without fine-tuning large multimodal encoders.
Anthology ID:
2026.mwe-1.15
Volume:
Proceedings of the 22nd Workshop on Multiword Expressions (MWE 2026)
Month:
March
Year:
2026
Address:
Rabat, Marocco
Editors:
Atul Kr. Ojha, Verginica Barbu Mititelu, Mathieu Constant, Ivelina Stoyanova, A. Seza Doğruöz, Alexandre Rademaker
Venues:
MWE | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
127–133
Language:
URL:
https://aclanthology.org/2026.mwe-1.15/
DOI:
Bibkey:
Cite (ACL):
Nina Hosseini-Kivanani. 2026. PolyFrame at MWE-2026 AdMIRe 2: When Words Are Not Enough: Multimodal Idiom Disambiguation. In Proceedings of the 22nd Workshop on Multiword Expressions (MWE 2026), pages 127–133, Rabat, Marocco. Association for Computational Linguistics.
Cite (Informal):
PolyFrame at MWE-2026 AdMIRe 2: When Words Are Not Enough: Multimodal Idiom Disambiguation (Hosseini-Kivanani, MWE 2026)
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PDF:
https://aclanthology.org/2026.mwe-1.15.pdf