Al-Qahera at Arabic Segmentation Shared Task 2026: Genre-Conditioned LLM Prompting versus Supervised Multi-Backbone Ensembling

Mohamed Mohamed, Hazem Ajlan


Abstract
We submit systems to both the closed and open divisions of all four tracks of the AraSeg 2026 shared task (PA, NP, NoPnx-PA, NoPnx-NP): a supervised 3-backbone ensemble (CAMeLBERT-MSA, AraBERTv02, and AraELECTRA, each with a gated-residual head, R-Drop regularization, and stochastic weight averaging), and a zero-shot LLM system prompted with explicit, track-specific segmentation rules instead of labeled examples. The ensemble uses no external resources, so it is entered in both divisions everywhere; for NoPnx-NP specifically, where every structural cue is stripped away, we additionally blend its predictions with the LLM system’s, in a real-data-only variant (closed-eligible) and a wiki-augmented variant trained with added pseudo-labeled Wikipedia data (open-only). On the officially-scored blind test, our best submission per track reaches 94.70 F1 (PA), 91.00 (NP), 91.20 (NoPnx-PA), and 87.40 (NoPnx-NP). The supervised ensemble is the stronger, more consistent choice overall; the one exception is NoPnx-PA, where our LLM system’s unmodified seed prompt outperforms it and combining the two systems does not help—the only track where that happens. We report in full the structural annotation ambiguities we uncovered while building the LLM system.
Anthology ID:
2026.arabicnlp-sharedtasks.124
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:
1010–1021
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.124/
DOI:
Bibkey:
Cite (ACL):
Mohamed Mohamed and Hazem Ajlan. 2026. Al-Qahera at Arabic Segmentation Shared Task 2026: Genre-Conditioned LLM Prompting versus Supervised Multi-Backbone Ensembling. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1010–1021, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Al-Qahera at Arabic Segmentation Shared Task 2026: Genre-Conditioned LLM Prompting versus Supervised Multi-Backbone Ensembling (Mohamed & Ajlan, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.124.pdf