Morocco

A detailed understanding of the basic properties of text collections produced by humans or generated synthetically is vital for all steps of the natural language processing system life cycle, from training to evaluating model performance and synthetic texts.
To facilitate the analysis of these properties, we introduce elfen, a Python library for efficient linguistic feature extraction for text datasets. It includes the largest set of item-level linguistic features in eleven feature areas: surface-level, POS, lexical richness, readability, named entity, semantic, information-theoretic, emotion, psycholinguistic, dependency, and morphological features. Building on top of popular NLP and modern dataframe libraries, elfen enables feature extraction in various languages ($80$ at the moment) on thousands of items, even given limited computing resources. We show how using elfen enables linguistically informed data selection, outlier detection, and text collection comparison.
We release elfen as an open-source PyPI package, accompanied by extensive documentation, including tutorials. We host the code at https://github.com/mmmaurer/elfen/, make it available through the GESIS Methods Hub at https://methodshub.gesis.org/library/methods/elfen/, and provide documentation and tutorials at https://elfen.readthedocs.io/en/latest/. A screencast showcasing elfen is available at https://youtu.be/b4pqHWn6UPU.

EACL 2026

elfen: A Python Package for Efficient Linguistic Feature Extraction for Natural Language Datasets

python package

feature extraction

linguistic features

### Welcome to ACL 2023, the 61st Annual Meeting of the Association for Computational Linguistics! 
 The conference will be held in Toronto, Canada, July 9-14, 2023. 
Following the succession of the recent conferences in our field, ACL 2023 will adopt a hybrid format.
While the impact of Covid has considerably diminished in terms of traveling, obtaining visas to Canada
entails a very long process. Moreover, the global economic conditions pose challenges for many individuals to travel to conferences. Recognizing these circumstances, we know many participants may not be
able to attend the conference in person. Therefore, we are committed to providing a great virtual platform
so everyone has the opportunity to interact with other participants and enjoy the conference. Based on the
current registered participants, approxiately 30% have chosen to attend the conference virtually. Whether
you join us in person or virtually, we sincerely hope everyone has a remarkable conference experience. 
This General Chair’s message is where I express my gratitude to the many individuals who have made
enormous contributions to the conference over the past year.

Read [**ACL 2023 General Chair's message**](https://docs.google.com/document/d/1WobYM7norbG4dI48s75HfJoD89qgX5a_F-6U8AteLSA/edit?usp=sharing/) in full.

##### **[Conference Handbook](https://2023.aclweb.org/downloads/acl2023-handbook.pdf)**

ACL 2023

The Association for Computational Linguistics (ACL) is the premier international scientific and professional society for people working on computational problems involving human language, a field often referred to as either computational linguistics or natural language processing.

demo

#### *Message from the General Chair, Aline Villavicencio*
I’m delighted and honoured to welcome you to the 19th Conference of the European Chapter of the Association for Computational Linguistics (EACL 2026), taking place in the beautiful city of Rabat, in Morocco, in March 24-29, 2026. EACL is the flagship European conference of the Association and EACL 2026 proudly continues our field’s tradition of excellence in scholarship, innovation, and inclusivity. I am deeply grateful to the many volunteers whose dedication, generosity, and tireless efforts have made this conference possible.
For the first time EACL is being hosted in the African continent. This is an important milestone for our community, and we are grateful to our Moroccan hosts for enabling this historic moment by bringing this edition of EACL to Rabat. We are also delighted that the Second Arabic NLP School is co-located with EACL. We hope attendees enjoy this wonderful opportunity to strengthen ties with the Computational Linguistics communities across the African continent. *[Read full message](https://drive.google.com/file/d/14NlmHvwM6fPJuMmOvVh7K0vtQbEyv3SZ/view?usp=sharing)* 

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Welcome to the 19th Conference of the European Chapter of the Association for Computational Linguistics (EACL). EACL 2026 will be held in Rabat, Morocco, from March 24–29, 2026. 

Recent advancements in Large Language Models (LLMs) have showcased their proficiency in answering natural language queries. However, their effectiveness is hindered by limited domain-specific knowledge, raising concerns about the reliability of their responses. We introduce a hybrid system that augments LLMs with domain-specific knowledge graphs (KGs), thereby aiming to enhance factual correctness using a KG-based retrieval approach. We focus on a medical KG to demonstrate our methodology, which includes (1) pre-processing, (2) Cypher query generation, (3) Cypher query processing, (4) KG retrieval, and (5) LLM-enhanced response generation. We evaluate our system on a curated dataset of 69 samples, achieving a precision of 78% in retrieving correct KG nodes. Our findings indicate that the hybrid system surpasses a standalone LLM in accuracy and completeness, as verified by an LLM-as-a-Judge evaluation method. This positions the system as a promising tool for applications that demand factual correctness and completeness, such as target identification --- a critical process in pinpointing biological entities for disease treatment or crop enhancement. Moreover, its intuitive search interface and ability to provide accurate responses within seconds make it well-suited for time-sensitive, precision-focused research contexts. We publish the source code together with the dataset and the prompt templates used.

Fact Finder - Enhancing Domain Expertise of Large Language Models by Incorporating Knowledge Graphs

We present ClinicalTrialsHub, an interactive search-focused platform that consolidates all data from ClinicalTrials.gov and augments it by automatically extracting and structuring trial-relevant information from PubMed research articles. Our system effectively increases access to structured clinical trial data by 83.8% compared to relying on ClinicalTrials.gov alone, with potential to make access easier for patients, clinicians, researchers, and policymakers, advancing evidence-based medicine. ClinicalTrialsHub uses large language models such as GPT-5.1 and Gemini-3-Pro to enhance accessibility. The platform automatically parses full-text research articles to extract structured trial information, translates user queries into structured database searches, and provides an attributed question-answering system that generates evidence-grounded answers linked to specific source sentences. We demonstrate its utility through a user study involving clinicians, clinical researchers, and PhD students of pharmaceutical sciences and nursing, and a systematic automatic evaluation of its information extraction and question answering capabilities.

ClinicalTrialsHub: Bridging Registries and Literature for Comprehensive Clinical Trial Access

While large language models (LLMs) excel at generating structured data, such as code, their ability to precisely manipulating it based on instructions remains relatively under-explored. Regular expressions (regexes), critical in practice, are challenging to manipulate. Crucially, the correctness of transformations can be mathematically verified, making them exceptionally well-suited for measuring the symbolic reasoning of LLMs. We introduce Query4Regex, a new benchmark for evaluating verifiable transformations on regexes. Our benchmark tests two query formats: natural language instructions and a program-like domain-specific language (DSL) that specifies the sequence of operations. We evaluate a range of LLMs, verifying semantic correctness through rigorous deterministic finite automata (DFA) equivalence testing. Our empirical studies reveal: 1) the formal DSL significantly outperforms natural language, achieving up to 6.74%p average accuracy gains. 2) Performance for both formats degrades sharply as compositional complexity increases, highlighting a core challenge in multi-step reasoning. 3) Models often generate syntactically valid but semantically incorrect regexes, making errors difficult to detect without formal verification. Query4Regex provides a robust framework for analyzing the gap between LLMs' linguistic fluency and their symbolic reasoning, paving the way for more reliable and verifiable manipulation of formal languages.

Query4Regex: Verifiable Regex Transformation through Formal Operations from NL and DSL Queries

Agentic AI systems, which build on Large Language Models (LLMs) and interact with tools and memory, have rapidly advanced in capability and scope. Yet, since LLMs have been shown to struggle in multilingual settings, typically resulting in lower performance and reduced safety, agentic systems risk inheriting these limitations. This raises concerns about the accessibility of such systems, as users interacting in languages other than English may encounter unreliable or security-critical agent behavior. Despite growing interest in evaluating agentic AI, existing benchmarks focus exclusively on English, leaving multilingual settings unexplored. To address this gap, we propose MAPS, a multilingual benchmark suite designed to evaluate agentic AI systems across diverse languages and tasks. MAPS builds on four widely used agentic benchmarks - GAIA (real-world tasks), SWE-bench (code generation), MATH (mathematical reasoning), and the Agent Security Benchmark (security). We translate each dataset into eleven diverse languages, resulting in 805 unique tasks and 9,660 total language-specific instances - enabling a systematic analysis of the multilingual effect on AI agents' performance and robustness. Empirically, we observe a degradation in both performance and security when transitioning from English to other languages, with severity varying by task and correlating with the amount of translated input. Building on these findings, we provide actionable recommendations to guide agentic AI systems development and assessment under multilingual settings. This work establishes the first standardized evaluation framework for multilingual agentic AI, encouraging future research towards equitable, reliable, and accessible agentic AI. The MAPS benchmark suite will become publicly available upon publication.

MAPS: A Multilingual Benchmark for Agent Performance and Security

Large Language Models (LLMs) are now state-of-the-art at summarization, yet the hidden notion of importance that drives their information selections remains hidden. We propose to address this by combining behavioral and computational analyses. Behaviorally, we generate length-controlled summaries and derive empirical importance distributions based on how often each information unit is selected. These reveal that LLMs converge on consistent importance patterns, sharply different from pre-LLM baselines, and that LLMs cluster more by size than by family. Computationally, we probe internal representations and find that middle layers strongly encode importance, and certain attention heads alone align well with empirical importance distributions. Together, these results provide initial insights about what LLMs prioritize in summarization and how this priority is internally represented, opening a path toward interpreting, and ultimately controlling, information selection in LLMs.

What Matters to an LLM? Behavioral and Computational Evidences from Summarization

Large language models (LLMs) achieve state-of-the-art performance in machine translation, but are also known to be sensitive to errors in user prompts. Given these models are largely trained on and respond best to prompts in standard English, this may affect the quality of LLM outputs for second language English speakers as well as real-world lay users, with potentially disproportionate effects on the former. We explore this effect by modeling a range of error types exhibited by such users, motivated by studies of L2 English, and quantifying their impact on LLM performance. We work with two related tasks: machine translation and machine translation evaluation. We find that LLMs-as-MT are brittle to natural spelling errors but not to errors at the phrasal level. However, the variance in quality caused by these errors is lower than the variance over the initial prompt choice, suggesting that ``perfect English'' for a given prompt is less important than choosing a good prompt. Since lay users and L2 speakers may use non-optimal prompts as well as display imperfect language skills, our work calls for increasing the resilience of model performance to both these phenomena to best serve a diverse user base, both from a robustness and fairness perspective.

How Important is ‘Perfect’ English for Machine Translation Prompts?

Practicing conversations with large language models (LLMs) presents a promising alternative to traditional in-person language learning. However, most LLMs generate text at a near-native level of complexity, making them ill-suited for beginner learners (CEFR: A1вЂ“A2). In this paper, we investigate whether controllable generation techniques can adapt LLM outputs to better support absolute beginners. We evaluate these methods through both automatic metrics and a user study with university-level learners of Japanese. Our findings show that while prompting alone fails, controllable generation techniques can successfully improve output comprehensibility for beginner speakers (from 40.4% to 84.3%). We further introduce a new token-level evaluation metric, Token Miss Rate (TMR), that quantifies the proportion of incomprehensible tokens per utterance and correlates strongly with human judgments. To support future research in AI-assisted language learning, we release our code, models, annotation tools, and dataset.

Toward Beginner-Friendly LLMs for Language Learning: Controlling Difficulty in Conversation

Instruction pre-training (IPT) has recently emerged as an effective intermediate stage between vanilla pre-training and post-training for large language models (LLMs). However, the optimal design of IPT corpora---such as the balance between raw and instruction-response data, languages, and task categories---remains unclear. We systematically study IPT corpus composition using a bilingual (English and Japanese) and multi-category (coding, general, math, and reasoning) instruction-response dataset. Through extensive IPT experiments across four base models, including both English-centric and bilingual LLMs, we find that: (1) more instruction-response data generally enhances model performance, particularly for models with large VPT budgets; (2) Japanese instruction data can improve English performance through cross-lingual transfer; and (3) the effectiveness of post-training varies across categories: coding performance is largely determined during IPT, while math and reasoning continue to improve during post-training.

Comprehensive Study of Bilingual and Multi-category Instruction Pre-training

Fact-checking on major platforms, such as X, Meta, and TikTok, is shifting from expert-driven verification to a community-based setup, where users contribute explanatory notes to clarify why a post might be misleading. An important challenge here is determining whether an explanation is helpful for understanding real-world claims and the reasons why, which remains largely underexplored in prior research. In practice, most community notes remain unpublished due to slow community annotation, and the reasons for helpfulness lack clear definitions. To bridge these gaps, we introduce the task of predicting both the helpfulness of explanatory notes and the reason for this. We present COMMUNITYNOTES, a large-scale multilingual dataset of 105k posts with user-provided notes and helpfulness labels. We further propose a framework that automatically generates and improves reason definitions via automatic prompt optimization, and integrate them into prediction. Our experiments show that the optimized definitions can improve both helpfulness and reason prediction. Finally, we show that the helpfulness information are beneficial for existing fact-checking systems.

COMMUNITYNOTES: A Dataset for Exploring the Helpfulness of Fact-Checking Explanations

Fine-tuning LLMs introduces many important behaviors, such as instruction following, safety alignment. This makes it crucial to study how fine-tuning changes models' internal mechanisms. Sparse autoencoders (SAEs) offer a powerful tool for interpreting neural networks by extracting concepts (features) represented in their activations. Previous work observed that SAEs trained on base models transfer effectively to instruction-tuned (chat) models, attributed to activation similarity. In this work, we propose *feature drift* as an alternative explanation: the feature space remains relevant, but the distribution of feature activations changes. In other words, fine-tuning recombines existing concepts rather than learning new ones. We validate this by showing base SAEs reconstruct both base and chat activations comparably despite systematic differences, with individual features exhibiting clear drift patterns. In a refusal behavior case study, we identify base SAE features that drift to activate on harmful instructions in chat models. Causal interventions using these features confirm that they mediate refusal. Our findings suggest that monitoring how existing features drift, rather than searching for entirely new features, may provide a more complete explanation of how fine-tuning changes model capabilities.

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