Semantics of Multiword Expressions in Transformer-Based Models: A Survey

Filip Miletić, Sabine Schulte im Walde


Abstract
Multiword expressions (MWEs) are composed of multiple words and exhibit variable degrees of compositionality. As such, their meanings are notoriously difficult to model, and it is unclear to what extent this issue affects transformer architectures. Addressing this gap, we provide the first in-depth survey of MWE processing with transformer models. We overall find that they capture MWE semantics inconsistently, as shown by reliance on surface patterns and memorized information. MWE meaning is also strongly localized, predominantly in early layers of the architecture. Representations benefit from specific linguistic properties, such as lower semantic idiosyncrasy and ambiguity of target expressions. Our findings overall question the ability of transformer models to robustly capture fine-grained semantics. Furthermore, we highlight the need for more directly comparable evaluation setups.
Anthology ID:
2024.tacl-1.33
Volume:
Transactions of the Association for Computational Linguistics, Volume 12
Month:
Year:
2024
Address:
Cambridge, MA
Venue:
TACL
SIG:
Publisher:
MIT Press
Note:
Pages:
593–612
Language:
URL:
https://aclanthology.org/2024.tacl-1.33
DOI:
10.1162/tacl_a_00657
Bibkey:
Cite (ACL):
Filip Miletić and Sabine Schulte im Walde. 2024. Semantics of Multiword Expressions in Transformer-Based Models: A Survey. Transactions of the Association for Computational Linguistics, 12:593–612.
Cite (Informal):
Semantics of Multiword Expressions in Transformer-Based Models: A Survey (Miletić & Walde, TACL 2024)
Copy Citation:
PDF:
https://aclanthology.org/2024.tacl-1.33.pdf