Categorize Early, Integrate Late: Divergent Processing Strategies in Automatic Speech Recognition

Nathan Roll, Pranav Bhalerao, Martijn Bartelds, Arjun Pawar, Yuka Tatsumi, Tolúlopé Ògúnrèmí, Chen Shani, Calbert Graham, Meghan Sumner, Dan Jurafsky


Abstract
In speech language modeling, two architectures dominate the frontier: the Transformer and the Conformer. However, it remains unknown whether their comparable performance stems from convergent processing strategies or distinct architectural inductive biases. We introduce Architectural Fingerprinting, a probing framework that isolates the effect of architecture on representation, and apply it to a controlled suite of 24 pre-trained encoders (39M–3.3B parameters). Our analysis reveals divergent hierarchies: Conformers implement a "Categorize Early" strategy, resolving phoneme categories 29% earlier in depth and speaker gender by 16% depth. In contrast, Transformers "Integrate Late," deferring phoneme, accent, and duration encoding to deep layers (49-57%). These fingerprints suggest design heuristics: Conformers’ front-loaded categorization may benefit low-latency streaming, while Transformers’ deep integration may favor tasks requiring rich context and cross-utterance normalization.
Anthology ID:
2026.emnlp-main.2333
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:
52997–53012
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URL:
https://aclanthology.org/2026.emnlp-main.2333/
DOI:
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Cite (ACL):
Nathan Roll, Pranav Bhalerao, Martijn Bartelds, Arjun Pawar, Yuka Tatsumi, Tolúlopé Ògúnrèmí, Chen Shani, Calbert Graham, Meghan Sumner, and Dan Jurafsky. 2026. Categorize Early, Integrate Late: Divergent Processing Strategies in Automatic Speech Recognition. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 52997–53012, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Categorize Early, Integrate Late: Divergent Processing Strategies in Automatic Speech Recognition (Roll et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2333.pdf