Lost in Speech: Benchmarking, Evaluation, and Parsing of Spoken Bilingual Conversational Language Beyond Standard UD Assumptions

Nemika Tyagi, Olga Kellert, Holly Hendrix, Nelvin Licona-Guevara, Justin Mackie, Phanos Kareen, Megan Michelle Smith, Tatiana Gallego Hernandez, Samhitha Harish, Chitta Baral


Abstract
Spoken bilingual conversations pose substantial challenges for syntactic parsing because they often include disfluencies and discourse-driven structures that complicate dependency parsing under standard Universal Dependencies (UD) assumptions and evaluation practices. To systematically study these challenges, in this work, we first introduce a linguistically grounded taxonomy of conversational bilingual phenomena, together with SpokeBench, an expert-annotated English-Spanish benchmark for structurally complex speech. To address the limitations of existing evaluation practices, we propose Flex-UD, an ambiguity-aware evaluation metric that distinguishes catastrophic structural failures from linguistically acceptable variations. Finally, we introduce DECAP, a decoupled agentic parsing framework that separates spoken-phenomena handling from core syntactic analysis, enabling robust and interpretable dependency parsing without retraining. Experiments across both proprietary and open-weight LLMs show that DECAP substantially improves performance on complex conversational phenomena and achieves over 60% improvements in UPOS-F1 Score over baselines, while Flex-UD evaluations reveal gains that otherwise remain partially hidden under standard attachment-based metrics.
Anthology ID:
2026.emnlp-main.1797
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
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SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
40948–40965
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URL:
https://aclanthology.org/2026.emnlp-main.1797/
DOI:
Bibkey:
Cite (ACL):
Nemika Tyagi, Olga Kellert, Holly Hendrix, Nelvin Licona-Guevara, Justin Mackie, Phanos Kareen, Megan Michelle Smith, Tatiana Gallego Hernandez, Samhitha Harish, and Chitta Baral. 2026. Lost in Speech: Benchmarking, Evaluation, and Parsing of Spoken Bilingual Conversational Language Beyond Standard UD Assumptions. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 40948–40965, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Lost in Speech: Benchmarking, Evaluation, and Parsing of Spoken Bilingual Conversational Language Beyond Standard UD Assumptions (Tyagi et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1797.pdf