Bengali is spoken by more than 230 million people, yet no standardized instrument evaluates large language models (LLMs) on Bengali across the task categories used to benchmark frontier models. We release 8 English benchmarks translated into Bengali with a single consistent pipeline and use them to evaluate 10 open LLMs from 4 families on paired English and Bengali inputs. Script fragmentation is what subword tokenizers do to Bengali’s alphasyllabary, whose written units are grapheme clusters spanning several Unicode code points: they cut the script into pieces smaller than a character, at a cost set by the vocabulary rather than the script itself. Format belongs to the evaluation, the answer shape that exact-match scoring demands regardless of whether the model knew the answer. Beyond confirming a substantial gap (macro LLM-judge score 0.79 in English versus 0.63 in Bengali), we show that part of it is a measurement artifact: exact-match accuracy conflates correctness with format adherence and because format failure is asymmetric across languages it distorts the apparent gap for some models three to five fold and even reverses its sign for one reasoning-tuned model. On the fragmentation side, Bengali costs roughly five times more tokens per word than English, the 10 models share only 4 vocabularies and that cost varies twofold across them (7.9 tokens per word under Llama3̃, 4.0 under Tekken), and under three of the four the average Bengali token spans fewer bytes than a single code point. Bengali is the constant here and the vocabularies are not, so what Bengali text costs is set by tokenizer design rather than by the script. Fertility and sequence length correlate only weakly with scores (r = -0.23), so we present this as a cost and segmentation concern rather than a driver of the gap. The datasets, pipeline and evaluation code are released.

Meme understanding goes beyond recognizing visual content or literal text; it requires implicit cultural knowledge and pragmatic inference that most vision-language models still lack. We introduce MemeCULT-1K, a multilingual benchmark of 1,000 South Asian memes in Bengali, English, and Hindi, where each meme is paired with a cultural context note and three human-written explanations, along with a supplementary set of 54 Bengali regional dialect memes. We evaluate thirteen popular Vision Language Models (VLMs) under two settings: meme-only and context-aware. Providing minimal cultural context yields consistent gains across all models and languages: mean SBERT similarity improves from 44.6 to 56.4 (+11.8), BLEURT from 37.3 to 42.3 (+5.0), and LLM-as-a-Judge scores from 2.57 to 3.43 out of 5 (+0.86). Fine-grained error analysis reveals that closed-source models fail mainly on entity and reference misidentification, while open-source models are bottlenecked by broader cultural knowledge gaps, with linguistic and phonological failures proving the most context-resistant across both. These results highlight the difficulty of culturally grounded meme understanding and motivate future work on explicit cultural knowledge integration. Our dataset and code are publicly available at TawsifDipto17/MemeCULT-1K.

Conventional research on speech recognition modeling relies on the canonical form for most low-resource languages while automatic speech recognition (ASR) for regional dialects is treated as a fine-tuning task. To investigate the effects of dialectal variations on ASR we develop a 78-hour annotated Bengali Speech-to-Text (STT) corpus named Ben-10. Investigation from linguistic and data-driven perspectives shows that speech foundation models struggle heavily in regional dialect ASR, both in zero-shot and fine-tuned settings. We observe that all deep learning methods struggle to model speech data under dialectal variations, but dialect specific model training alleviates the issue. Our dataset also serves as a out-of-distribution (OOD) resource for ASR modeling under constrained resources in ASR algorithms. The dataset and code developed for this project are publicly available.