DxMultiHead at AraSeg Shared Task 2026: Alignment-Safe Sequence Labeling and Weighted Ensembling for Arabic Sentence Segmentation

Muhammad Bahaa Alsayed Eid, Mohamed Khaled, Mena Hany


Abstract
Sentence boundary detection in Arabic is inherently challenging due to ambiguous orthographic punctuation conventions, prolific coordinating conjunction clitics, and extensive stylistic variability across literary, religious, news, and web domains. In this paper, we present our system submission to the Closed Track of the AraSeg 2026 Shared Task. We formulate sentence boundary detection as a token-level sequence classification problem utilizing an ensemble of fine-tuned Arabic Transformer encoders: AraBERTv02, CAMeLBERT-MSA, and ARBERTv2. Our pipeline integrates an alignment-safe normalization strategy that strictly preserves gold token spans, overlapping sliding-window logit margin aggregation to counteract chunk-boundary degradation, stochastic punctuation masking during training, and calibrated positive-class loss weighting. In the official blind evaluation across eight diverse genres, our framework demonstrated strong boundary recovery across all four task tracks, securing 2nd place in both the Paragraph-Aware setting (F1 = 95.0%) and the No-Paragraph setting (F1 = 91.3%).
Anthology ID:
2026.arabicnlp-sharedtasks.118
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:
956–960
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.118/
DOI:
Bibkey:
Cite (ACL):
Muhammad Bahaa Alsayed Eid, Mohamed Khaled, and Mena Hany. 2026. DxMultiHead at AraSeg Shared Task 2026: Alignment-Safe Sequence Labeling and Weighted Ensembling for Arabic Sentence Segmentation. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 956–960, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DxMultiHead at AraSeg Shared Task 2026: Alignment-Safe Sequence Labeling and Weighted Ensembling for Arabic Sentence Segmentation (Eid et al., ArabicNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.118.pdf