CIS-OpenSLU at NADI 2026 Shared Task: ASR-Matched Training and Confidence-Based Rejection for Open-Set Tunisian Arabic Intent Recognition

Salma Khaled Hegazy


Abstract
Open-set spoken intent recognition for low-resource Arabic varieties must handle both automatic speech recognition (ASR) errors and intents absent from training. We describe CIS-OpenSLU, our NADI 2026 Task 5.1 system, which transcribes Tunisian Arabic speech with Whisper Turbo and classifies the resulting text using word- and character-level TF–IDF features with a LinearSVC. On ASR-transcribed validation audio, training the classifier on Whisper-generated transcripts rather than gold transcripts raises weighted F1 from 49.25% to 69.78%, showing that matching training and inference text distributions is crucial. We rank test utterances by the maximum SVM decision score and reject low-confidence examples as unknown; the final system achieves 71.54% weighted F1 and 72.50% accuracy, ranking second. Auxiliary audio and multi-modal experiments further show that strong unseen-intent detection in leave-one-intent-out simulation does not necessarily transfer to genuinely unseen test intents.
Anthology ID:
2026.arabicnlp-sharedtasks.8
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Muhammad Abdul-Mageed, Tamer Elsayed, Houda Bouamor, Samhaa El-Beltagy, Hend Al-Khalifa, Ahmed Abdelali, AbdelRahim Elmadany, Abdellah El Mekki, Kareem Darwish, Sakhar Alkhereyf, Hamzah Luqman, Salam Khalifa, Samar Magdy, Zaid Alyafeai, Injy Hamed, Wajdi Zaghouani, Imed Zitouni
Venue:
ArabicNLP
SIG:
SIGARAB
Publisher:
Association for Computational Linguistics
Note:
Pages:
72–78
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.8/
DOI:
Bibkey:
Cite (ACL):
Salma Khaled Hegazy. 2026. CIS-OpenSLU at NADI 2026 Shared Task: ASR-Matched Training and Confidence-Based Rejection for Open-Set Tunisian Arabic Intent Recognition. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 72–78, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CIS-OpenSLU at NADI 2026 Shared Task: ASR-Matched Training and Confidence-Based Rejection for Open-Set Tunisian Arabic Intent Recognition (Hegazy, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.8.pdf