DR-RAG: Addressing Retrieval Misalignment in Low-Resource Urdu Question Answering
Saad Ahmad, Muhammad Hammad, Muhammad Zeeshan, Faizad Ullah, Asim Karim
Abstract
Retrieval-Augmented Generation performs well on English QA benchmarks, but degrades considerably in morphologically rich, low-resource languages. Urdu presents a particularly challenging case: heavy inflectional morphology, Nastaliq script inconsistencies, and limited training data produce a systematic mismatch between query representations and indexed document content that standard retrieval architectures cannot bridge. We propose DR-RAG (Dual-Representation Retrieval-Augmented Generation), which addresses this through dual indexing. Each document is represented as overlapping text chunks and as automatically generated question-answer pairs. Queries are first matched against the QA index, which aligns more reliably with natural query phrasing than declarative document chunks. When retrieval confidence falls below τ = 0.80, the system falls back to chunk-based retrieval, maintaining coverage without sacrificing precision. Evaluated on Urdu UQA and English SQuAD 2.0, DR-RAG improves Urdu METEOR by 38×, ROUGE-1 by 140%, and reduces generation latency by 43%. LLM-as judge scores show higher faithfulness (3.03 vs 1.93) and overall quality (2.99 vs 2.21) over MultiVector. English performance remains competitive throughout. These results indicate that representation-level alignment between queries and indexed content, rather than increased model complexity, is the critical factor for reliable retrieval in underserved South Asian languages.- Anthology ID:
- 2026.chipsal-1.6
- Volume:
- Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026)
- Month:
- May
- Year:
- 2026
- Address:
- Palma de Mallorca, Spain
- Editors:
- Kengatharaiyer Sarveswaran, Ashwini Vaidya
- Venues:
- CHiPSAL | WS
- SIG:
- Publisher:
- ELRA Language Resources Association (ELRA)
- Note:
- Pages:
- 49–58
- Language:
- External URL:
- https://lrec.elra.info/lrec2026-ws-chipsal-06
- DOI:
- 10.63317/4wwyss5zkwxs
- Cite (ACL):
- Saad Ahmad, Muhammad Hammad, Muhammad Zeeshan, Faizad Ullah, and Asim Karim. 2026. DR-RAG: Addressing Retrieval Misalignment in Low-Resource Urdu Question Answering. In Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026), pages 49–58, Palma de Mallorca, Spain. ELRA Language Resources Association (ELRA).
- Cite (Informal):
- DR-RAG: Addressing Retrieval Misalignment in Low-Resource Urdu Question Answering (Ahmad et al., CHiPSAL 2026)