Probing Semantic Alignment, Lexical Invariance, and Syntactic Influence in LLM Metaphor Processing

Fengying Ye, Shanshan Wang, Lidia S. Chao, Derek F. Wong


Abstract
Large language models (LLMs) achieve strong performance on metaphor detection and interpretation tasks, yet it remains unclear what such behavioral success actually reveals about metaphor processing. We present a diagnostic analysis that examines the limits of behavioral evidence by probing three complementary dimensions: semantic attribute alignment, lexical invariance, and syntactic sensitivity. Using geometric probing, we assess whether model-generated interpretations align with reference semantic attributes; through context-varying substitution, we analyze the stability of lexical associations between metaphorical and literal expressions; and via controlled syntactic perturbations, we examine sensitivity in metaphor detection. Our analysis reveals that LLM-generated interpretations can exhibit semantic drift relative to reference attributes; stable lexical anchors persist across contextual conditions, potentially supporting conventional metaphors while biasing novel metaphors requiring contextual integration; and detection performance is sensitive to syntactic irregularities. These findings suggest that strong behavioral performance may reflect heterogeneous underlying signals, highlighting the need for caution when interpreting metaphor benchmarks as evidence of robust, integrated semantic understanding.
Anthology ID:
2026.acl-long.1286
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
27914–27932
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1286/
DOI:
Bibkey:
Cite (ACL):
Fengying Ye, Shanshan Wang, Lidia S. Chao, and Derek F. Wong. 2026. Probing Semantic Alignment, Lexical Invariance, and Syntactic Influence in LLM Metaphor Processing. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 27914–27932, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Probing Semantic Alignment, Lexical Invariance, and Syntactic Influence in LLM Metaphor Processing (Ye et al., ACL 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1286.pdf
Checklist:
 2026.acl-long.1286.checklist.pdf