NAMAA at DialectSentEval 2026 Subtask 2: From Reranked Sampling to Cross-Backbone Ensembling for Arabic Dialectal Sentiment Swap

Hassan Barmandah, Yousra Alaa El-Ghawi, Mona A.Azim, Omer Nacar


Abstract
Arabic sentiment swap aims to reverse the polarity of a dialectal sentence while preserving its underlying meaning. We present NAMAA’s system for DialectSentEval 2026 Subtask 2. Fine-tuning AraT5v2 achieves 79.56 development sentiment-style accuracy, while reranked sampling over eight candidates, using sentiment agreement and content-overlap signals, raises this to 93.57. Cross-backbone ensembling further reaches a development score of 96.78. On the hidden test set, however, this ordering does not transfer: a widened rerank pool with a re-tuned content weight achieves our best official score of 0.7597, whereas the most complex all-source ensemble scores 0.7343. We identify two likely contributors to this development-to-test mismatch: the absence of gold source-polarity labels at test time, which requires classifier-based polarity inference, and train–development sentence duplication that may inflate development performance. These results show that additional generation and ensemble complexity can improve development metrics substantially without guaranteeing better generalization under shifted evaluation conditions.
Anthology ID:
2026.arabicnlp-sharedtasks.182
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:
1436–1440
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.182/
DOI:
Bibkey:
Cite (ACL):
Hassan Barmandah, Yousra Alaa El-Ghawi, Mona A.Azim, and Omer Nacar. 2026. NAMAA at DialectSentEval 2026 Subtask 2: From Reranked Sampling to Cross-Backbone Ensembling for Arabic Dialectal Sentiment Swap. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1436–1440, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
NAMAA at DialectSentEval 2026 Subtask 2: From Reranked Sampling to Cross-Backbone Ensembling for Arabic Dialectal Sentiment Swap (Barmandah et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.182.pdf