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
Aug 25

GRACE: Step-Level Benchmark for Faithful Reasoning over Context

GRACE is a step‑level benchmark for evaluating the faithfulness of chain‑of‑thought reasoning over context. It provides human annotations for each step in CoT traces from 10 models across 4 datasets, labeling faithfulness, error category, and natural‑language explanations. The benchmark introduces a data‑driven taxonomy that splits errors into GRACE‑Inference (deductive) and GRACE‑Grounding (factual) tracks, each with four categories, and demonstrates that incorporating step‑level faithfulness signals can improve downstream accuracy and reasoning reliability.

By Hoang Pham, Dong Le, Anh Tuan Luu
arXiv Computation and Language
Aug 25

Dialects of Translationese Shape Language Model Learning

The paper investigates how machine‑translated English data from 24 diverse source languages influences small English language models. It finds that source language affects model behavior: lexical diversity drives overall perplexity, while grammatical performance correlates with typological similarity to English when sufficient data is used. Additionally, translation quality strongly predicts language‑modeling performance.

By Jenny Kunz
arXiv AI
Aug 25

An Empirical Study on Preference Tuning Generalization and Diversity Under Domain Shift

The paper investigates how preference tuning—optimizing language models with explicit preference signals—behaves when applied to new domains. It systematically compares five alignment objectives and several adaptation strategies, such as target‑domain supervised fine‑tuning and pseudo‑labeling, across summarization, question‑answering helpfulness, and safety tasks. Results show that while pseudo‑labeling reduces domain‑shift degradation, it also causes mode collapse, highlighting a trade‑off between generalization and diversity.

By Constantinos Karouzos, Xingwei Tan, Nikolaos Aletras
arXiv AI
Aug 25

SDoH-Aware Narrative Anchoring Bias in Medical LLMs for Trustworthy Clinical Decision Support

The paper investigates how medical large language models (LLMs) may exhibit narrative anchoring bias when presented with the same clinical case in different patient voices. Using the NarrativeShield SDoH MedQA dataset, the authors evaluate three Qwen2.5 instruction‑tuned LLMs (1.5B, 3B, 7B) on 300 clinical cases, reporting metrics such as persona‑level accuracy, counterfactual consistency, correct consistency, and narrative sensitivity error. The 7B model achieves the highest accuracy (56.33 %) and correct consistency (40.33 %), yet narrative sensitivity errors remain substantial (31.67 %).

By Ahnaf Atef Choudhury, Ramkrishna Saha
arXiv Computation and Language
Aug 25

N\"urnberg NLP @ GermEval Shared Task 2026: Harmful Content Detection in German Social Media through Error-Independent LLM Voters

The paper reports on the N"urnberg NLP team’s system for the GermEval 2026 shared task on harmful content detection in German social media. The authors tackle severe class imbalance by building a nine‑voter ensemble that varies along three orthogonal axes—LLM choice, training method, and class scope—to achieve error independence. Their system attains macro‑F1 scores of 89.56 (C2A), 71.63 (DBO), 54.84 (VIO), and 83.02 (DEF) on the hidden test set, winning all four subtasks.

By Philipp Steigerwald, Eric Rudolph, Jens Albrecht
arXiv AI
Aug 25

Lexical Perturbations Disrupt LLM Reasoning: An Empirical Study of Attention Diversion

The study investigates how lexical perturbations—such as keyboard noise, character swaps, and filler insertion—affect large language models (LLMs) on reasoning benchmarks. Four open-weight instruction-tuned models and frontier models were evaluated, revealing that character-level perturbations significantly reduce accuracy, especially on multi-step reasoning tasks, while filler insertion has minimal impact. The authors attribute this asymmetry to Attention Diversion, where fragmented subword tokenization draws disproportionate attention in middle and final transformer layers; they demonstrate that both token content and attention allocation are coupled, making it difficult for inference-time repair strategies to fully recover performance.

By Jiaqian Zhu, Yang Zhang, Junhua Ding, Xiaowei Yu