MechPunBench: A Bilingual Mechanism-Centered Benchmark for Pun Understanding and Generation

Tianwei Zhang, Zihan Gu, Jiayu Wang, Tianyi Ma, Jiacheng Lu, Jinyu Li, Hua Zhang


Abstract
Puns pose a challenging test case for large language models (LLMs), as their interpretation requires mapping a surface expression to an implicit meaning through a specific pun-forming mechanism. Existing benchmarks typically evaluate isolated abilities such as detection, localization, explanation, or generation quality, leaving unclear whether LLMs can consistently identify, explain, and apply the mechanisms that make puns work. To address this gap, we introduce MECHPUNBENCH, a bilingual, mechanism-oriented benchmark for Chinese and English pun understanding and generation. Each positive instance is annotated with trigger spans, surface meanings, implicit meanings, rhetorical effects, and mechanism labels. Based on a taxonomy of Lexical-Semantic, Structural-Syntactic, and Structural-Semantic puns, we formulate six diagnostic tasks spanning surface recognition to mechanism-guided generation. Experiments on representative closed-source and open-source LLMs reveal a substantial surface–mechanism gap: although the best model achieves 82.8% detection accuracy and 88.2% containment localization accuracy, it remains below the 4/5 threshold used in our evaluation on implicit meaning explanation, mechanism explanation, rhetorical effect explanation, and mechanism-consistent generation. These findings suggest that recognizing puns or generating fluent pun-like text does not necessarily indicate robust mechanism-level pun understanding.
Anthology ID:
2026.findings-emnlp.1385
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
29473–29500
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1385/
DOI:
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Cite (ACL):
Tianwei Zhang, Zihan Gu, Jiayu Wang, Tianyi Ma, Jiacheng Lu, Jinyu Li, and Hua Zhang. 2026. MechPunBench: A Bilingual Mechanism-Centered Benchmark for Pun Understanding and Generation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 29473–29500, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MechPunBench: A Bilingual Mechanism-Centered Benchmark for Pun Understanding and Generation (Zhang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1385.pdf