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Fake News Classification in Urdu: A Domain Adaptation Approach for a Low-Resource Language

Muhammad Zain Ali, Bernhard Pfahringer, Tony Smith

TL;DR

This work tackles misinformation detection in Urdu, a low-resource language, by applying domain-adaptive pretraining to two multilingual transformers (XLM-RoBERTa and mBERT) using a large Urdu news corpus before downstream fine-tuning on four Urdu fake-news datasets. The authors demonstrate that domain-adapted XLM-R consistently improves classification performance across datasets, while domain-adapted mBERT yields mixed results, despite substantial perplexity reductions. The findings highlight the importance of model choice in domain adaptation for low-resource languages and provide a replicable framework for enhancing Urdu NLP tasks through domain-aware pretraining and careful fine-tuning. Overall, the study advances fake-news detection in Urdu and offers practical guidance for deploying domain-adaptive transformer models in low-resource settings.

Abstract

Misinformation on social media is a widely acknowledged issue, and researchers worldwide are actively engaged in its detection. However, low-resource languages such as Urdu have received limited attention in this domain. An obvious approach is to utilize a multilingual pretrained language model and fine-tune it for a downstream classification task, such as misinformation detection. However, these models struggle with domain-specific terms, leading to suboptimal performance. To address this, we investigate the effectiveness of domain adaptation before fine-tuning for fake news classification in Urdu, employing a staged training approach to optimize model generalization. We evaluate two widely used multilingual models, XLM-RoBERTa and mBERT, and apply domain-adaptive pretraining using a publicly available Urdu news corpus. Experiments on four publicly available Urdu fake news datasets show that domain-adapted XLM-R consistently outperforms its vanilla counterpart, while domain-adapted mBERT exhibits mixed results.

Fake News Classification in Urdu: A Domain Adaptation Approach for a Low-Resource Language

TL;DR

This work tackles misinformation detection in Urdu, a low-resource language, by applying domain-adaptive pretraining to two multilingual transformers (XLM-RoBERTa and mBERT) using a large Urdu news corpus before downstream fine-tuning on four Urdu fake-news datasets. The authors demonstrate that domain-adapted XLM-R consistently improves classification performance across datasets, while domain-adapted mBERT yields mixed results, despite substantial perplexity reductions. The findings highlight the importance of model choice in domain adaptation for low-resource languages and provide a replicable framework for enhancing Urdu NLP tasks through domain-aware pretraining and careful fine-tuning. Overall, the study advances fake-news detection in Urdu and offers practical guidance for deploying domain-adaptive transformer models in low-resource settings.

Abstract

Misinformation on social media is a widely acknowledged issue, and researchers worldwide are actively engaged in its detection. However, low-resource languages such as Urdu have received limited attention in this domain. An obvious approach is to utilize a multilingual pretrained language model and fine-tune it for a downstream classification task, such as misinformation detection. However, these models struggle with domain-specific terms, leading to suboptimal performance. To address this, we investigate the effectiveness of domain adaptation before fine-tuning for fake news classification in Urdu, employing a staged training approach to optimize model generalization. We evaluate two widely used multilingual models, XLM-RoBERTa and mBERT, and apply domain-adaptive pretraining using a publicly available Urdu news corpus. Experiments on four publicly available Urdu fake news datasets show that domain-adapted XLM-R consistently outperforms its vanilla counterpart, while domain-adapted mBERT exhibits mixed results.
Paper Structure (28 sections, 1 equation, 11 figures, 3 tables)

This paper contains 28 sections, 1 equation, 11 figures, 3 tables.

Figures (11)

  • Figure 1: Proposed Architecture. (left side) Basic fine-tuning; (right side) Domain Adaptation + Fine-Tuning. PLM = Pre-trained Language Model.
  • Figure 2: Domain Adaptation (Masked Language Model) Loss Curves for XLM-R model
  • Figure 3: Domain Adaptation (Masked Language Model) Loss Curves for mBERT model
  • Figure 4: Loss and Accuracy curves for Classifier trained on Ax-to-Grindharris2023ax using XLM-R models
  • Figure 5: Loss and Accuracy curves for Classifier trained on UFN2023farooq2023fake using XLM-R models
  • ...and 6 more figures