HCMUS_The Fangs at AbjadStyleTransfer Shared Task: Learning to Query Style, Contrastive Representations for Zero-Shot Arabic Authorship Style Transfer
Summary
The paper presents the top-ranked system in the AbjadStyleTransfer shared task (ArabicNLP 2026). The task is to rewrite formal Modern Standard Arabic so that it reads like a given literary author. The team's data analysis showed that none of the 21 test authors, among them Naguib Mahfouz, Taha Hussein and Khalil Gibran, appear in the training set of 32,784 authors. This makes the problem purely zero-shot.
Because author-ID or classifier-based conditioning cannot generalize under these conditions, the authors built a dual-encoder model. An AraBERT encoder is trained contrastively to place texts in a normalized style space. The resulting style vector is then added to the hidden states of an AraT5 generator.
The system reaches 19.77 BLEU and 55.74 chrF, ahead of retrieval-augmented and multi-task baselines. More elaborate style-injection designs performed markedly worse. The authors conclude that pre-trained Arabic models already hold much stylistic knowledge about famous writers. Light conditioning that leaves this knowledge intact works better than heavy architectural changes. This gives practical guidance for low-resource and zero-shot style transfer.
Key points
- Data:
- Training: 35,122 samples from 32,784 authors, most of whom contribute a single text.
- Validation: 4,157 samples.
- Test: 8,413 samples from 21 famous authors.
- Author overlap between train and test is 0%.
- Architecture:
- Style encoder: AraBERT-base [CLS] output passed through a two-layer MLP, giving a 256-dimensional L2-normalized style embedding.
- Generator: AraT5, with the style embedding added through a shared projection to all encoder layers.
- Training objective:
- Generation loss, plus a SimCSE-style contrastive loss with dropout-based positives (τ = 0.07), plus 0.1 × an auxiliary classification loss.
- Trained on a single T4 GPU with an effective batch size of 32 for 3 epochs.
- Results on the private test set (BLEU / chrF):
- Contrastive system: 19.77 / 55.74.
- Retrieval-augmented baseline (FAISS, k = 3): 16.68 / 49.63.
- Multi-task baseline: 15.07 / 47.45.
- Style injection variants underperform badly:
- Cross-attention injection scores 9.63 BLEU.
- Prompting with the author's name scores 6.54 BLEU.
- Evaluation used only automatic metrics, with no human or stylometric assessment.
Cite
@inproceedings{sy2026hcmus,
title = {{HCMUS\_The Fangs at AbjadStyleTransfer Shared Task: Learning to Query Style, Contrastive Representations for Zero-Shot Arabic Authorship Style Transfer}},
author = {Sy, Duy Minh Dao and Huynh, Trung Kiet and Tran, Nguyen Chi and Quy, Nguyen Lam Phu and Hoa, Pham Phu and Duong, Nguyen Dinh Ha},
booktitle = {Proceedings of the 2nd Workshop on NLP for Languages Using Arabic Script},
year = {2026},
doi = {10.18653/v1/2026.abjadnlp-1.52},
url = {https://doi.org/10.18653/v1/2026.abjadnlp-1.52}
}References
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