Austria

Large language models (LLMs) have shown strong performance across natural language reasoning tasks, yet their reasoning processes remain brittle and difficult to interpret. Prompting techniques like Chain-of-Thought (CoT) enhance reliability by eliciting intermediate reasoning steps or aggregating multiple outputs. However, they lack mechanisms for enforcing logical structure and assessing internal coherence. We introduce Theorem-of-Thought (ToTh), a novel framework that models reasoning as collaboration among three parallel agents, each simulating a distinct mode of inference: abductive, deductive, and inductive. Each agent produces a reasoning trace, which is structured into a formal reasoning graph. To evaluate consistency, we apply Bayesian belief propagation guided by natural language inference (NLI), assigning confidence scores to each step. The most coherent graph is selected to derive the final answer. Experiments on symbolic (WebOfLies) and numerical (MultiArith) reasoning benchmarks show that ToTh consistently outperforms CoT, Self-Consistency, and CoT-Decoding across multiple LLMs, while producing interpretable and logically grounded reasoning chains. Our findings suggest a promising direction for building more robust and cognitively inspired LLM reasoning. The implementation is available at https://github.com/KurbanIntelligenceLab/theorem-of-thought.

ACL 2025

Theorem-of-Thought: A Multi-Agent Framework for Abductive, Deductive, and Inductive Reasoning in Language Models

It is my great pleasure and honor to welcome you to the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), held in San Diego, California, USA, July 2–7, 2026. ACL 2026 continues our fields tradition of excellence in scholarship, innovation, and inclusivity, and I am deeply grateful to the many volunteers who have worked tirelessly to bring this event to life.

It is exciting to see the many developments in the field reflected at our conference, such as the advancement of large language models (born out of our community) into many application directions. This is not without challenges, partly due to unsolved problems, and partly due to misuse of the technology. All this is reflected well at ACL 2026. The conference also reflects that the field is not only about advancing technology, but also the science of fundamentally understanding language and how it is use by many different speaker communities. 
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ACL 2026

The 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026) will take place in San Diego, California, from July 2 - 7, 2026.

workshop paper

### Welcome to The 63rd Annual Meeting of the Association for Computational Linguistics (ACL 2025)

Message from the General Chair: 
*It is my great pleasure and honor to welcome you to the 63rd Annual Meeting of the Association for Computational Linguistics (ACL 2025), held in beautiful Vienna, Austria, from July 27 to August 1, 2025. ACL2025continues our field’s tradition of excellence in scholarship, innovation, and inclusivity, and I am deeply grateful to the many volunteers who have worked tirelessly to bring this event to life.* 
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Welcome to The 63rd Annual Meeting of the Association for Computational Linguistics (ACL 2025)

Chinese homophones, prevalent in Internet culture, bring rich linguistic twists that are challenging for language models. While native speakers disambiguate them through phonological reasoning and contextual understanding, it remains untested how well LLMs perform on this task and whether LLMs also achieve this via similar reasoning processes or merely through memorization of homophone-original word pairs during training.

In this paper, we present HomoP-CN, the first Chinese Internet homophones dataset with systematic perturbations for evaluating LLMs' homophone restoration capabilities. Using this benchmark, we investigated the influence of semantic, phonological, and graphemic features on LLMs' restoration accuracy, measured the reliance levels of each model on memorization during restoration through consistency ratios under controlled perturbations, and assessed the effectiveness of various prompting strategies, including contextual cues, pinyin augmentation, few-shot learning, and thought-chain approaches.

Reasoning or Memorization? Investigating LLMs’ Capabilit in Restoring Chinese Internet Homophones

Large language models (LLMs) achieve high performance through instruction-tuning, which involves learning various tasks using instruction templates. However, these templates often contain task-specific expressions, which are words that frequently appear in certain contexts but do not always convey the actual meaning of that context, even if they seem closely related to the target task. Biases inherent in such instruction templates may be learned by LLMs during training, potentially degrading performance when the models encounter superficial expressions. In this study, we propose a method that incorporates additional instructions to FLAN templates, without altering the base instruction to produce "superfluous instructions". This allows us to investigate the vulnerabilities of LLMs caused by overfitting to task-specific expressions embedded in instruction templates. The experimental results revealed that the inclusion of superficial words strongly related to each task in the instruction text can alter the output, regardless of the intended meaning.

Superfluous Instruction: Vulnerabilities Stemming from Task-Specific Superficial Expressions in Instruction Templates

Dense vector representations have become foundational to modern natural language processing (NLP), powering diverse workflows from semantic search and retrieval augmented generation to content comparison across languages. 
Although Wikipedia is one of the most comprehensive and widely used datasets in modern NLP research, it lacks a fully reproducible and permissively licensed dense vectorization.
In this paper, we present Wikivecs, a fully reproducible, permissively licensed dataset containing dense vector embeddings for every article in Multilingual Wikipedia. 
Our pipeline leverages a fully reproducible and permissively licensed multilingual text encoder to embed Wikipedia articles into a unified vector space, making it easy to compare and analyze content across languages.
Alongside these vectors, we release a two-dimensional data map derived from the vectors, enabling visualization and exploration of Multilingual Wikipedia’s content landscape.
We demonstrate the utility of our dataset by identifying several content gaps between English and Russian Wikipedia.

Wikivecs: A Fully Reproducible Vectorization of Multilingual Wikipedia

Specialized entity linking (EL) models are well-trained at mapping mentions to unique knowledge base (KB) entities according to a given context.
However, specialized EL models struggle to disambiguate long-tail entities due to their limited training data.
Meanwhile, extensively pre-trained large language models (LLMs) possess broader knowledge of uncommon entities.
Yet, with a lack of specialized EL training, LLMs frequently fail to generate accurate KB entity names, limiting their standalone effectiveness in EL.
With the observation that LLMs are more adept at context generation instead of EL execution, 
we introduce LLM-Augmented Entity Linking (LLMAEL), 
the first framework to enhance specialized EL models with LLM data augmentation.
LLMAEL leverages off-the-shelf, tuning-free LLMs as context augmenters, generating entity descriptions to serve as additional input for specialized EL models.
Experiments show that LLMAEL sets new state-of-the-art results across 6 widely adopted EL benchmarks: compared to prior methods that integrate tuning-free LLMs into EL, LLMAEL achieves an absolute 8.9\% gain in EL accuracy. 
We release our datasets and models to facilitate future research.

LLMaEL: Large Language Models are Good Context Augmenters for Entity Linking

Wikipedia, as a massively multilingual, community-driven platform, is a valuable resource for Natural Language Processing (NLP), yet the consistency of honorific usage in honorific-rich languages remains underexplored.
Honorifics, subtle yet profound linguistic markers, encode social hierarchies, politeness norms, and cultural values, but Wikipedia's editorial guidelines lack clear standards for their usage in languages where such forms are grammatically and socially prevalent. 
This paper addresses this gap through a large-scale, analysis of third-person honorific pronouns and verb forms in Hindi and Bengali Wikipedia articles. Using Large Language Models (LLM), we automatically annotate $10,000$ articles per language for honorific usage and socio-demographic features such as gender, age, fame, and cultural origin.
We investigate: (i) the consistency of honorific usage across articles, (ii) how inconsistencies correlate with socio-cultural factors, and (iii) the presence of explicit or implicit biases across languages.
We find that honorific usage is consistently more common in Bengali than Hindi, while non-honorific forms are more frequent for infamous, juvenile, and exotic entities in both. Notably, gender bias emerges in both languages, particularly in Hindi, where men are more likely to receive honorifics than women.
Our analysis highlights the need for Wikipedia to develop language-specific editorial guidelines for honorific usage.

Women, Infamous, and Exotic Beings: What Honorific Usages in Wikipedia Reflect on the Cross-Cultural Sociolinguistic Norms?

Given Wikipedia’s role as a trusted source of high-quality, reliable content, there are growing concerns about the proliferation of low-quality machine-generated text (MGT) produced by large language models (LLMs) on its platform. Reliable detection of MGT is therefore essential, yet existing work primarily evaluates MGT detectors on generic generation tasks, rather than on tasks more commonly performed by Wikipedia editors. This misalignment can lead to poor generalisability when applied to real-world Wikipedia contexts.
We introduce WETBench, a multilingual, multi-generator, and task-specific benchmark for MGT detection. We define three editing tasks empirically grounded in Wikipedia editors’ perceived use cases for LLM-assisted editing: Paragraph Writing, Summarisation, and Text Style Transfer, which we implement using two new datasets across three languages. For each writing task, we evaluate three prompts, produce MGT across multiple generators using the best-performing prompt, and benchmark diverse detectors.
We find that, across settings, training-based detectors achieve an average accuracy of 78%, while zero-shot detectors average 58%. These results demonstrate that detectors struggle with MGT in realistic generation scenarios and underscore the importance of evaluating such models on diverse, task-specific data to assess their reliability in editor-driven contexts.

WETBench: A Benchmark for Detecting Task-Specific Machine-Generated Text on Wikipedia

Wikipedia is powered by MediaWiki, a free and open-source software that is also the infrastructure for many other wiki-based online encyclopedias. These include the recently launched website Ruwiki, which has copied and modified the original Russian Wikipedia content to conform to Russian law. To identify practices and narratives that could be associated with different forms of knowledge manipulation, this article presents an in-depth analysis of this Russian Wikipedia fork. We propose a methodology to characterize the main changes with respect to the original version. The foundation of this study is a comprehensive comparative analysis of more than 1.9M articles from Russian Wikipedia and its fork. Using meta-information and geographical, temporal, categorical, and textual features, we explore the changes made by Ruwiki editors. Furthermore, we present a classification of the main topics of knowledge manipulation in this fork, including a numerical estimation of their scope. This research not only sheds light on significant changes within Ruwiki, but also provides a methodology that could be applied to analyze other Wikipedia forks and similar collaborative projects.

Characterizing Knowledge Manipulation in a Russian Wikipedia Fork

Proper nouns in Arabic Wikipedia are frequently undiacritized, creating ambiguity in pronunciation and interpretation, especially for transliterated named entities of foreign origin. While transliteration and diacritization have been well-studied separately in Arabic NLP, their intersection remains underexplored. In this paper, we introduce a new manually diacritized dataset of Arabic proper nouns of various origins with their English Wikipedia equivalent glosses, and present the challenges and guidelines we followed to create it. We benchmark GPT-4o on the task of recovering full diacritization given the undiacritized Arabic and English forms, and analyze its performance. Achieving 73\% accuracy, our results underscore both the difficulty of the task and the need for improved models and resources. We release our dataset to facilitate further research on Arabic Wikipedia proper noun diacritization.

Proper Noun Diacritization for Arabic Wikipedia: A Benchmark Dataset

Wikipedia serves millions of readers daily with multimedia articles, but its content is not equally accessible to all. Visually impaired readers who rely on screen readers can access only a small fraction of images due to missing alt text.
We explore the potential of multimodal generative AI (GPT-4o) to generate high-quality alt text for Wikipedia images. Guided by accessibility best practices, we design four prompting strategies that incorporate writing guidelines and the textual context surrounding each image.
We evaluate these strategies through crowdsourcing, expert review, and a study involving blind and low-vision (BLV) readers. Crowd worker evaluations show that combining context and guidelines significantly improves alt-text quality, earning six times more majority votes than the baseline. Expert editors confirm these results and, through qualitative analysis, identify recurring issues related to accuracy, relevance, formatting, screen reader compatibility, and inclusive representation.
Interviews with BLV users reveal a consistent preference for context- and criteria-grounded alt text, along with concrete recommendations for improving description quality.
This work offers practical guidance for developing AI-assisted tools to help editors make Wikipedia more accessible.

Can LLMs Improve Image Accessibility on Wikipedia?

Malicious sockpuppet detection on Wikipedia is critical to preserving access to reliable information on the internet and preventing the spread of disinformation. Prior machine learning approaches rely on stylistic and meta-data features, but do not prioritise adaptability to author-specific behaviours. As a result, they struggle to effectively model the behaviour of specific sockpuppet-groups, especially when text data is limited. To address this, we propose the application of meta-learning, a machine learning technique designed to improve performance in data-scarce settings by training models across multiple tasks. Meta-learning optimises a model for rapid adaptation to the writing style of a new sockpuppet-group. Our results show that meta-learning significantly enhances the precision of predictions compared to pre-trained models, marking an advancement in combating sockpuppetry on open editing platforms. We release an updated dataset of sockpuppet investigations to foster future research in both sockpuppetry and meta-learning fields.

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Next from ACL 2025

Reasoning or Memorization? Investigating LLMs’ Capabilit in Restoring Chinese Internet Homophones

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Is Chain-of-Thought Reasoning of LLMs a Mirage? A Data Distribution Lens

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