Beyond Decodability: Reconstructing Language Model Representations with an Encoding Probe

Gaofei Shen, Martijn Bentum, Tomas Ostar Lentz, Afra Alishahi, Grzegorz Chrupała


Abstract
Probing is widely used to study which features can be decoded from language model representations. However, the common decoding probe approach has two limitations that we aim to solve with our new encoding probe approach: contributions of different features to model representations cannot be directly compared, and feature correlations can affect probing results. We present an Encoding Probe that reverses this direction and reconstructs internal representations of models using interpretable features. We evaluate this method on text and speech transformer models, using feature sets spanning acoustics, phonetics, syntax, lexicon, and speaker identity. Our results suggest that speaker-related effects vary strongly across different training objectives and datasets, while syntactic and lexical features contribute independently to reconstruction. These results show that the Encoding Probe provides a complementary perspective on interpreting model representations beyond decodability.
Anthology ID:
2026.emnlp-main.654
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
15033–15049
Language:
URL:
https://aclanthology.org/2026.emnlp-main.654/
DOI:
Bibkey:
Cite (ACL):
Gaofei Shen, Martijn Bentum, Tomas Ostar Lentz, Afra Alishahi, and Grzegorz Chrupała. 2026. Beyond Decodability: Reconstructing Language Model Representations with an Encoding Probe. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 15033–15049, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Beyond Decodability: Reconstructing Language Model Representations with an Encoding Probe (Shen et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.654.pdf