Durham-Jazan at Daleel 2026: Domain-Routed Ensembles, LLM Augmentation, and the Limits of Decision-Rule Tuning for Arabic Argument Mining

Amal Saad Alshehri, Nelly Bencomo, Housam Babiker, Amir Atapour-Abarghouei


Abstract
We describe the Durham-Jazan submissions to the Daleel 2026 shared task on Arabic argumentative discourse mining, which comprises multi-label paragraph classification (Task 1) and argumentative span detection (Task 2), each with a Closed and an Open track. Our Task 2 Closed system routes the Modern Standard Arabic editorials to CAMeLBERT and the noisier debate transcripts to MARBERTv2. The Open system blends the two families at character level and adds synthetic training data from a large language model for rare-class generalisation, generated by a segment-concatenation recipe that makes span offsets exact by construction. The Task 1 systems add back-translation, targeted augmentation of the rare classes, and a QLoRA-tuned Qwen3-32B for the editorials. Everything else trains on one 16 GB consumer GPU. Our official test scores are 0.729 and 0.736 overlap-F1 on Task 2 and 0.657 and 0.669 macro-F1 on Task 1 (Closed and Open). We placed first of two on Task 1 Open, first of one on Task 2 Open, fifth of ten on Task 1 Closed, and sixth of eight on Task 2 Closed. Our central finding concerns our own systems on this data. Recalibrating per-class thresholds on validation outputs overfits them. Under a controlled protocol the held-out effect is negative at every tuning-set size we tested, while the apparent in-sample gain shrinks as the tuning set grows. An audit of eighteen interventions from our campaign is consistent with this, though observational. A size-matched study links the editorial deficit that every team showed to the genre composition of the training data. We release our code and synthetic data.
Anthology ID:
2026.arabicnlp-sharedtasks.166
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:
1328–1343
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.166/
DOI:
Bibkey:
Cite (ACL):
Amal Saad Alshehri, Nelly Bencomo, Housam Babiker, and Amir Atapour-Abarghouei. 2026. Durham-Jazan at Daleel 2026: Domain-Routed Ensembles, LLM Augmentation, and the Limits of Decision-Rule Tuning for Arabic Argument Mining. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1328–1343, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Durham-Jazan at Daleel 2026: Domain-Routed Ensembles, LLM Augmentation, and the Limits of Decision-Rule Tuning for Arabic Argument Mining (Alshehri et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.166.pdf