Causal Interventions Reveal Typologically Organized Syntactic Mechanisms in Multilingual Language Models

Abstract:Linguistic theory has long recognized cross-linguistic syntactic regularities, leading to claims that these similar structures are processed by similar mechanisms. However, this hypothesis has been difficult to test empirically due to our lack of fine-grained, manipulable access of human processing mechanisms. In this work, we take advantage of techniques from mechanistic interpretability to study such a question in multilingual LMs. We first isolate language-internal mechanisms before attempting to transfer them cross-lingually. Across four models and three well-studied constructions (subject--verb number agreement, anaphoric pronoun gender agreement, and filler--gap object extraction) we find consistent cross-lingual mechanism transfer. We further find transfer to be graded, with more transfer between more typologically similar languages. We believe our work provides novel hypotheses about cross-linguistic syntactic structures and multilingual processing, and more broadly shows how the study of language models can help inform linguistic theory.

Computation and Language (cs.CL)

arXiv:2608.28924 [cs.CL]

(or arXiv:2608.28924v1 [cs.CL] for this version)

https://doi.org/10.48550/arXiv.2608.28924 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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