BenHalluEval: A Multi-Task Hallucination Evaluation Framework for Large Language Models on Bengali

Fuente: arXiv
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Autori principali: Adib, Shefayat E Shams, Sani, Ahmed Alfey, Esham, Ekramul Alam, Abrar, Ajwad, Tashdeed, Ishmam, Chowdhury, Md Taukir Azam
Natura: Preprint
Pubblicazione: 2026
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author Adib, Shefayat E Shams
Sani, Ahmed Alfey
Esham, Ekramul Alam
Abrar, Ajwad
Tashdeed, Ishmam
Chowdhury, Md Taukir Azam
author_facet Adib, Shefayat E Shams
Sani, Ahmed Alfey
Esham, Ekramul Alam
Abrar, Ajwad
Tashdeed, Ishmam
Chowdhury, Md Taukir Azam
contents Despite Bengali being the sixth most spoken language in the world, no prior work has systematically evaluated hallucination in large language models (LLMs) for Bengali. We introduce BenHalluEval, a fine-grained hallucination evaluation framework for Bengali covering four tasks: Generative Question Answering (GQA), Bangla-English Code-Mixed QA, Summarization, and Reasoning. We construct 12,000 hallucinated candidates using GPT-5.4 across twelve task-specific hallucination types, drawn from three existing Bengali datasets, and evaluate seven LLMs spanning reasoning-oriented, multilingual, and Bengali-centric categories under a dual-track protocol that independently measures false-positive rate on ground-truth instances (Track A) and hallucination detection rate on hallucinated candidates (Track B). To jointly penalise both failure modes and prevent inflated scores from uniform response bias, we propose BenHalluScore, a dual-track calibration metric that ranges from 7.72% to 55.42% across models and tasks, revealing substantial variation in hallucination calibration. Chain-of-thought prompting, applied as a mitigation strategy, shifts response distributions without consistently improving hallucination discrimination. BenHalluEval establishes the first dedicated hallucination benchmark for Bengali and highlights the inadequacy of single-track and prompting-only evaluation approaches for low-resource language settings. The dataset and code are available at https://anonymous.4open.science/r/BanglaHalluEval-EB77.
format Preprint
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publishDate 2026
record_format arxiv
spellingShingle BenHalluEval: A Multi-Task Hallucination Evaluation Framework for Large Language Models on Bengali
Adib, Shefayat E Shams
Sani, Ahmed Alfey
Esham, Ekramul Alam
Abrar, Ajwad
Tashdeed, Ishmam
Chowdhury, Md Taukir Azam
Computation and Language
Artificial Intelligence
Despite Bengali being the sixth most spoken language in the world, no prior work has systematically evaluated hallucination in large language models (LLMs) for Bengali. We introduce BenHalluEval, a fine-grained hallucination evaluation framework for Bengali covering four tasks: Generative Question Answering (GQA), Bangla-English Code-Mixed QA, Summarization, and Reasoning. We construct 12,000 hallucinated candidates using GPT-5.4 across twelve task-specific hallucination types, drawn from three existing Bengali datasets, and evaluate seven LLMs spanning reasoning-oriented, multilingual, and Bengali-centric categories under a dual-track protocol that independently measures false-positive rate on ground-truth instances (Track A) and hallucination detection rate on hallucinated candidates (Track B). To jointly penalise both failure modes and prevent inflated scores from uniform response bias, we propose BenHalluScore, a dual-track calibration metric that ranges from 7.72% to 55.42% across models and tasks, revealing substantial variation in hallucination calibration. Chain-of-thought prompting, applied as a mitigation strategy, shifts response distributions without consistently improving hallucination discrimination. BenHalluEval establishes the first dedicated hallucination benchmark for Bengali and highlights the inadequacy of single-track and prompting-only evaluation approaches for low-resource language settings. The dataset and code are available at https://anonymous.4open.science/r/BanglaHalluEval-EB77.
title BenHalluEval: A Multi-Task Hallucination Evaluation Framework for Large Language Models on Bengali
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2605.31483