Natural language processing

Classical and neural NLP: translation, question answering, tokenization and the evaluation of language understanding.

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arXiv Computation and Language
Sep 25

ChunkRank: Model-Aware Text Chunking and Abstention-Aware Answer Selection for LLM Pipelines

ChunkRank is an open‑source Python library that automatically determines chunk boundaries based on a target model’s tokenizer and context window, and then selects an answer from independently produced chunk candidates. It includes a registry of 90 models from 15 providers and six answer‑selection methods, and requires only three core dependencies. Experiments show that token‑exact budgeting is important across 11 languages, and that for several datasets no content‑based ranker outperforms simply taking the first non‑empty answer due to reader abstention on chunks lacking the answer.

By Amit Nautiyal, Ayush Bhatt, Gaurav Nautiyal
arXiv Computation and Language
Sep 25

Encoded but Not Decoded: Layer-Localized Evidence for a Three-Level Gap in LLM Syntax

The paper introduces a three-level evaluation framework—behavioral deployment, LM-head readout, and probe recoverability—to distinguish whether a language model fails a syntactic test by not encoding structure or by failing to use it. Using a trilingual control-dependency benchmark, the authors find that probe recoverability consistently exceeds LM-head readout, which in turn exceeds behavioral deployment across seven models and three languages, with the largest gap observed in Qwen3-0.6B Instruct. Layer-localized activation patching shows that instruction tuning shifts the decoded layer later, suggesting decoding favors surface shortcuts and that behavioral evaluation understates what models encode while probing alone overstates what they deploy.

By Zhenyan Lu, He Wang, Xiaohui Huang
arXiv Computation and Language
Sep 25

Language Specific Knowledge: Do Models Know Better in X than in English?

The paper introduces the concept of Language Specific Knowledge (LSK), showing that multilingual language models can answer certain queries better when prompted in a language other than English, sometimes even in low‑resource languages. It defines a language‑selection problem and presents several baseline methods, including the authors’ LSKExtractor, to empirically demonstrate that choosing the optimal language can improve question‑answering performance across datasets covering cultural and social norms. Experiments reveal non‑intuitive mappings, such as Gemma models excelling on Chinese and Middle Eastern topics in Spanish and Qwen models performing best on authority and responsibility queries in Arabic and Chinese.

By Ishika Agarwal, Nimet Beyza Bozdag, Dilek Hakkani-T\"ur
arXiv AI
Sep 25

Automated Regulatory Compliance Question Answering in Financial Services with Domain-Adapted Retrieval-Augmented Generation

The paper presents a retrieval‑augmented generation pipeline for answering regulatory compliance questions in finance. It builds a three‑stage retriever on LegalBERT and a compact 2B–12B generator served with 4‑bit quantization, achieving a Recall@10 of 0.774 on the ObliQA benchmark and improving answer quality via RAFT‑LoRA fine‑tuning. However, the adapted models fail to transfer to Australian case‑law questions, and a closed‑book model performs almost as well while lacking verifiable grounding.

By Tobias Deu{\ss}er, Abhishek Pillai, Aurelio F. Bariviera, Dhananjay Bhardwaj, Lorenz Sparrenberg, David Berghaus, Christian Bauckhage, Rafet Sifa
arXiv Machine Learning
Sep 25

Spectral-Guided Diffusion: Accelerating Inference via Static Spectral Layer Scheduling

Spectral-Guided Diffusion introduces a method to accelerate diffusion inference by identifying and reusing residual branches that need not be recomputed during the trajectory. The approach uses a Spectral Concentration Ratio (SCR) combined with Frobenius magnitude to create an offline sensitivity proxy and deterministic lifetime for each scheduled unit, eliminating the need for routers or input-dependent searches. Experiments on models such as LLaDA-8B, DiT-XL/2, U-ViT-L, and SDXL show that this scheduling preserves quality better than several baselines and achieves up to a 3.0× wall‑clock speedup over eager inference.

By Ibne Farabi Shihab, Abu Sa-Adat Mohamed Moon-Im Al Ahsan, Anuj Sharma
arXiv Computation and Language
Sep 25

Confident but Wrong: A Constrained Decoding Diagnostic for Low-Resource Automatic Post-Editing

The paper introduces a black‑box, inference‑time diagnostic for low‑resource Automatic Post‑Editing (APE) that distinguishes whether poor performance is due to insufficient training data or inconsistent training signals. By varying an edit‑distance penalty and analyzing the resulting TER‑vs‑λ curve and confidence‑based constraint ordering, the authors identify two failure modes—Binary Collapse and Confident Miscalibration—across multiple language pairs. The diagnostic also suggests practical next steps, such as applying a static constraint for immediate accuracy gains, and the authors release new English‑Sinhala and English‑Tamil APE datasets with accompanying code.

By Isuru Wijesiri, Nisansa de Silva, Kavindu Warnakulasuriya, Aloka Fernando, Surangika Ranathunga
arXiv Computation and Language
Sep 25

Continued Pretraining of FinBERT on Finnish Histopathological Reports: Train-Time Signals and Proxy Downstream Correlations

The paper investigates continued pretraining (CPT) of the Finnish BERT model (FinBERT) on a Finnish histopathological dataset, noting that CPT train‑time loss curves vary significantly across domains. Since the histopathology data lacks labels, the authors use public Finnish datasets as proxy data to examine whether CPT‑derived signals correlate with downstream classification gains. Their exploratory analysis finds that certain CPT features are associated with improved proxy classification performance, adding to the sparse literature on Finnish healthcare NLP.

By Rami Luisto, Liisa Pet\"ainen, Tommi Gr\"onholm, Jan B\"ohm, Maarit Ahtiainen, Tomi Lilja, Ilkka P\"ol\"onen, Sami \"Ayr\"am\"o
arXiv Computation and Language
Sep 25

Closing the Quality Gap in Low-Resource Text-to-Speech: LoRA Fine-Tuning of VoxCPM2 for Khmer and Korean

The paper investigates how to close the quality gap in low‑resource text‑to‑speech for Khmer and Korean using the VoxCPM2 model. By training a single low‑rank adaptation (LoRA) adapter on a shared 25.5‑hour corpus, the authors improve Khmer’s mean opinion score from 3.85 to 4.23 with a rank‑64 adapter, while Korean shows no significant gain. The study highlights that adaptation benefits mainly when the base model is weak and that training loss does not always align with human ratings.

By Phannet Pov, Hyun Woo Park, Voneat Pen, Sovandara Chhoun, Wan-Sup Cho, Saksonita Khoeurn
arXiv Computer Vision
Sep 25

A Hybrid CNN--State-Space--Attention Backbone with Joint-Embedding Predictive Pretraining for 12-Lead ECG Classification

The paper presents a hybrid CNN–state‑space–attention backbone designed for 12‑lead ECG classification, combining early waveform tokenization, mixed temporal dynamics modeling, and late global attention. It introduces an ECG‑oriented Joint‑Embedding Predictive Pretraining (JEPA) that samples span masks at latent resolution and predicts clean latent targets via a momentum encoder, avoiding waveform reconstruction. Experiments on CPSC2018, Chapman‑Shaoxing, and PTB‑XL, with pretraining on ~350K unlabeled CODE‑15 recordings, demonstrate strong supervised baselines and improved transfer, especially in low‑label scenarios and with LoRA adaptation.

By Yakoub Bazi, Sarah Aljuhani, Mohamad M. Al Rahhal, Mansour Zuair, Naif Alajlan
arXiv AI
Sep 25

Technical Manual for Toolkit for Confidence-Corpus Consistency via Fine-Tuning on a Fabricated Corpus

The article presents a technical manual for an open toolkit designed to evaluate how a language model’s confidence reflects its factual knowledge. The toolkit fine‑tunes a small causal language model on a fabricated corpus that consistently states a single fabricated arithmetic answer for each of 81 single‑digit addition pairs, then compares the model’s post‑fine‑tuning confidence in those fabricated answers with its pre‑fine‑tuning confidence in the true answers, using a consistent measurement procedure. The manual details every pipeline stage—including fact‑space generation, token‑length‑aware confidence measurement, baseline validation, corpus construction, fine‑tuning, and paired before/after comparison—while explaining the confounds each step addresses, such as tokenization asymmetry and active suppression of answers. "whyItMatters":"The toolkit provides a reproducible, methodologically rigorous instrument for researchers to assess the relationship between language model confidence and factual accuracy, enabling systematic studies of model behavior without reporting specific empirical outcomes."

By Jos\'e Luciano Ver\c{c}osa Marques, Frederico Jorge Heitmann, Daniel Omar Perez, Reinaldo Cesar, Marcelo Vinicius de Paula, T\'arcio Andr\'e dos Santos Barros
arXiv Machine Learning
Sep 25

A Computational Framework for Modelling Organisation-Level Semantic Identity from Longitudinal Textual Data

The paper presents a new computational framework for modelling organisation-level semantic identity using longitudinal textual data. It combines semantic representation learning, graph-based modelling, and temporal analysis to create interpretable semantic fingerprints that capture diversity, concentration, connectivity, novelty, and community composition. The framework is validated on a corpus of K‑pop lyrics from major South Korean entertainment companies, revealing distinct, evolving semantic identities that are statistically robust and reproducible.

By Brinda Murali Krishna, Oktay Karaku\c{s}, Can Eyupoglu
arXiv Computation and Language
Sep 25

COILD: An Indic-Centric Parallel Corpus and Benchmark for Machine Translation Across Indian Languages

COILD is an Indic‑centric parallel corpus that contains over 1.16 million human‑translated and verified sentence pairs across 20 Indian language pairs from four language families. The corpus is sourced from original Indian language materials in eight domains, and a 2,000‑sentence domain‑centric benchmark is provided for consistent multilingual evaluation. Experiments with IndicTrans2‑Distilled and NLLB‑200 show consistent improvements in automatic metrics and human judgments, underscoring the value of high‑quality Indic‑centric data.

By Kshetrimayum Boynao Singh, Nitin Kumar Mishra, Palash Pratim Dutta, Atai Waris Khan, Aparna Kaushik, Avinash Kumar, Deeksha, Deepak Kumar, Saroj Kumar Jha, Saloka Sengupta, Anansa Roy, Umalatha Kannoth, Saifulla Samar, Meena Sharma, Manpreet Kaur, Jyoti Sharma, Ashwini Vaidya, Muralikrishna SN, Md Shad Akhtar, Poonam Bansal, Amita Dev, Sanasam Ranbir Singh, Samit Bhattacharya, Tanmoy Chakraborty, Asif Ekbal
arXiv AI
Sep 25

Ingest-Time Fact Compilation for Cost-Efficient and Reliable Question Answering over Revised Corpora

The paper introduces ingest‑time fact compilation, an architecture that preprocesses and compiles corpus data into self‑contained facts with resolved revisions, deletions, and source trust. By storing this compiled state, query‑time models can retrieve answers directly, avoiding costly reconstruction from raw passages. Experiments show that this approach reduces read cost per question by 12.89× and token usage by 21.6× while maintaining accuracy.

By Kyle Wild, Yusuke Takahashi, Asako Uraki
arXiv AI
Sep 25

Broadening Uncertainty Estimation for Audio Question Answering Across Methods, Formats, and Inputs

The study evaluates various uncertainty estimation methods—probability-based, sampling-based, self-verification, evidential, and contrastive—across four open-weight audio-language models and five audio QA benchmarks. In multiple-choice settings, first-token probability measures outperform others, achieving a mean AUROC of .740, while open-ended evaluation shows lower accuracy but still predictive uncertainty. Ablation experiments reveal that removing audio evidence significantly degrades error-detection performance, indicating that uncertainty relies more on audio than on question text.

By Aaron Isidore Grace, Weiran Wang
arXiv AI
Sep 25

Cross-Country Code-Mixing for Generative Recommendation

Cross-Country Code-Mixing for Generative Recommendation (CMRec) is a framework that enhances generative recommendation across different countries by injecting cross-country supervision at the data level. It learns a shared semantic codebook from multi-modal content and behavioral co-occurrence, then synthesizes mixed-country sequences through token-level substitutions that respect both static and dynamic constraints. A context-aware loss reweights these mixed samples based on their plausibility, leading to improved recommendation quality in data-sparse countries while maintaining performance in data-rich markets, as demonstrated by significant gains in advertising revenue and orders in real-world e-commerce experiments.

By Yuan Gao, Hao Deng, Haibo Xing, Yi Xu, Lingyu Mu, Jinxin Hu, Yu Zhang, Xiaoyi Zeng
arXiv AI
Sep 25

The Tokens Remember: When Tokenization Bypasses Knowledge Editing and Unlearning

The paper investigates how tokenization can undermine post‑release guarantees that sensitive knowledge has been edited or unlearned from open‑weight large language models. By showing that alternative valid tokenizations can bypass localized modifications, the authors introduce Toketive, a reference‑free attack that detects modified knowledge and reconstructs pre‑edit responses using only the released model. Experiments on five LLMs, six datasets, and six editing techniques reveal that 38.6% of alternative tokenizations recover suppressed information, with Toketive achieving high detection and reconstruction accuracy.

By Manit Baser, Aditya Nawal, Dinil Mon Divakaran, Mohan Gurusamy
arXiv AI
Sep 25

Human Agreement and Return Association Are Not Interchangeable Criteria

The paper examines whether human agreement and return association can be used interchangeably as criteria for validating sentiment tools in financial NLP. Using a large corpus of securities class action messages linked to abnormal stock returns, the authors compare five sentiment instruments and find that the relationship between human agreement and predictive validity varies with sampling conventions and score representations. They conclude that benchmark agreement establishes semantic validity but does not guarantee predictive rankings, and that message volume in a spam‑heavy conversation does not predict market damage or settlement size.

By AS Aravinthakshan, Laven Srivastava, Harsh Nandwani
arXiv AI
Sep 25

Foundations of Large Language Models

Foundations of Large Language Models is a book that focuses on core concepts of large language models rather than exhaustive coverage of the latest technologies. It is organized into six chapters covering pre‑training, generative models, prompting, alignment, inference, and reasoning. The book targets college students, professionals, and practitioners in NLP and related fields, serving as a reference for anyone interested in large language models.

By Tong Xiao, Jingbo Zhu
arXiv Machine Learning
Sep 25

Language Specificity vs. Domain Diversity: Benchmarking Transformers for Bangla Medical NER

This study benchmarks transformer models for Bangla medical named entity recognition (NER), comparing BanglaBERT, multilingual BERT (mBERT), XLM‑RoBERTa, and GPT‑4o mini under zero‑shot and few‑shot prompting. Across a full test set of 3,179 samples, fine‑tuned XLM‑RoBERTa achieves a new state‑of‑the‑art F1‑score of 0.5959, while BanglaBERT lags with 0.4937, suggesting that domain diversity outweighs language specificity. The analysis shows high performance on Medicine and Specialist entities (F1 > 0.83) but lower accuracy on Symptoms (F1 0.4367), and demonstrates that fine‑tuned transformers outperform prompt‑only approaches by a factor of 3.76.

By Rakib Abdullah, Md. Maruful Islam Maruf
arXiv Machine Learning
Sep 25

Named Entity Recognition using Sliding Window Approach

The paper presents an inference-only pipeline that extends the frozen NER model MahaNER‑BERT to document‑level prediction using overlapping sliding windows, eliminating the need for retraining or architectural changes. The approach is evaluated on six document‑level corpora derived from the MahaNER test set, employing two repetition strategies (Normal Repeat and Random Repeat) at three length levels and various window configurations. Results show the model maintains a macro F1‑score of up to 0.8902 with minimal variation, outperforming non‑windowed methods by avoiding boundary‑fragmentation errors and achieving more stable document‑level performance.

By Hariom Ingle, Ronit Ghode, Ishwari Gondkar, Jidnyasa Harad, Ravindra Murumkar, Raviraj Joshi