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
Bibkey:
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)
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