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Many kinds of logical systems have been employed in constructing formal languages to model phonological phenomena. A common theme among them is that the systems compile into finite automata. Two questions naturally arise. Can a given phenomenon be described with another logical system? And, if so, what is that description?

To the first question, algebraic techniques are well established through deep connections with logic and automata. To the second, the situation is less clear. Translations from automata are established for first-order and monadic second-order logics under precedence, but these may not translate easily to the simpler systems we often use. Translations for simple cases of restricted propositional logic (strictly local or strictly piecewise languages) are established, but insufficient to describe attested phenomena.

The present work establishes a general way to handle many systems in between. Specifically, we show how to translate between certain kinds of algebraic varieties $\mathbf{V}$ (systems defined by universally satisfied identities) and associated logical systems, then use decomposition to handle classes of the form $\mathbf{V}\ast\mathbf{D}$, where the notion of “symbol” is replaced by “$k$-block”. With this, we handle several (unrestricted) propositional logics, facilitating logical description of natural language.

ACL 2026

A Family of Effective Methods for Decompiling Canonical Acceptors, Instantiated for Languages of Dot-Depth One and Tier-Based Extensions

factoring

finite-state automata

automata

algebra

formal languages

ECAI2020 featured a full programme of technical papers, as well as many AI-related events of interest for researchers, students and all attendants who are interested on contemporary AI, including:




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ECAI 2020

ECAI 2020 featured a full programme of technical papers, as well as many AI-related events of interest for researchers, students and all attendants who are interested on contemporary AI.

workshop paper

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

Large language models (LLMs) exhibit remarkable few-shot learning capabilities, yet the role of syntactic structure in demonstration examples remains unexplored. Drawing on psycholinguistic research on structural priming, we investigate whether syntactic patterns in few-shot prompts influence LLM outputs and task performance. We conduct systematic experiments across four model families (Llama, Mistral, Qwen, Gemma) using four syntactic constructions (passive voice, cleft sentences, dative alternation, particle placement). Our results reveal robust syntactic priming effects, with priming strength ranging from 1.3× to 6.4× depending on construction type, indicating that models are substantially more likely to produce constructions matching demonstration syntax. Critically, we find that priming strength shows a positive trend with model size (r = 0.85, p = 0.068), with effects intensifying from 7B to 14B parameter models. We demonstrate that priming is construction-specific rather than reflecting general stylistic preferences, and that priming effects persist across multiple intervening sentences. Analysis across three task types (sentence completion, paraphrase generation, story continuation) reveals that syntactic structure in demonstrations influences output style, and that models produce primed constructions even when the task calls for a different syntactic form. These findings have immediate implications for prompt engineering and reveal that LLMs encode syntactic abstractions beyond surface-level pattern matching. We release our benchmark, SyntaxPrime-ICL, containing controlled examples across multiple constructions for evaluating syntactic priming in few-shot contexts.

Syntactic Priming in Few-Shot Learning: How Demonstration Structure Shapes LLM Performance

Nonsensical and anomalous sentences have been instrumental in the development of computational models of semantic interpretation. A core challenge is to distinguish between what is merely anomalous (but can be interpreted given a supporting context) and what is truly nonsensical. However, it is unclear (a) how nonsensical, rather than merely anomalous, existing datasets are; and (b) how well LLMs can make this distinction. In this paper, we answer both questions by collecting sensicality judgments from human raters and LLMs on sentences from five semantically deviant datasets---both context-free and when providing a context. We find that raters consider most sentences at most anomalous, and only a few as properly nonsensical. We also show that LLMs are substantially skilled in generating plausible contexts for anomalous cases.

Finding Sense in Nonsense with Generated Contexts: Perspectives from Humans and Language Models

Lexical Semantic Change Detection (LSCD) is a complex, lemma-level task, which is usually operationalized based on two subsequently applied usage-level tasks: First, Word-in-Context (WiC) labels are derived for pairs of usages. Then, these labels are represented in a graph on which Word Sense Induction (WSI) is applied to derive sense clusters. Finally, LSCD labels are derived by comparing sense clusters over time. This modularity is reflected in most LSCD datasets and models. It also leads to a large heterogeneity in modeling options and task definitions, which is exacerbated by a variety of dataset versions, preprocessing options and evaluation metrics. This heterogeneity makes it difficult to evaluate models under comparable conditions, to choose optimal model combinations or to reproduce results. Hence, we provide a benchmark repository standardizing LSCD evaluation. Through transparent implementation results become easily reproducible and by standardization different components can be freely combined. The repository reflects the task's modularity by allowing model evaluation for WiC, WSI and LSCD. This allows for careful evaluation of increasingly complex model components providing new ways of model optimization. We use the implemented benchmark to conduct a number of experiments with recent models and systematically improve the state-of-the-art.

The LSCD Benchmark: a Testbed for Diachronic Word Meaning Tasks

Making texts clear and comprehensible has become an increasingly important topic in NLP. A possible strategy to enhance text comprehension is to make implicitly conveyed meaning explicit. To explore the role of explicit vs. implied meaning, we study cases of so-called explicitations, i.e. revisions of text in which implicitly conveyed content is made explicit. Using revision histories from wikiHow, we propose a rule-based approach to extract candidate explicitations and curate a human-annotated dataset in which explicitations are distinguished from insertions of new information. Our analyses show that while the extraction method is effective in retrieving relevant cases, distinguishing explicitations from new information is a challenging and often subjective task, reflecting differences in background knowledge and reasoning. Experimentally, we find off-the-shelf LLMs to achieve promising performance, with inconsistent gains from few-shot prompting and fine-tuning. In contrast, fine-tuned NLI models benefit consistently from supervised training and show stronger robustness under distribution shift. In sum, our findings show that the task is challenging, but also indicate that our annotated dataset contains informative signals that models can learn from, paving the way for further research on explicitations.

Can You Be More Explicit? A Task and Dataset on Explicitations of Implicit Meaning

Evaluating the quality of automatically generated text often relies on LLM-as-a-judge (LLM-judge) methods. While effective, these approaches are computationally expensive and require post-processing. To address these limitations, we build upon ParaPLUIE, a perplexity-based LLM-judge metric that estimates confidence over “Yes/No” answers without generating text. We introduce *-PLUIE, task-specific prompting variants of ParaPLUIE and evaluate their alignment with human judgement. Our experiments show that personalised *-PLUIE achieves stronger correlations with human ratings while maintaining low computational cost.

*-PLUIE: Personalisable metric with Llm Used for Improved Evaluation

Stance detection seeks to determine whether a text expresses a position in favor of, against, or neutral toward a target. Despite advances in neural architectures, performance remains inconsistent across datasets. To better understand these disparities, we analyze over 75K samples from four benchmark datasets using six neural models, focusing on stylistic and 
pragmatic language features rather than architectures or external knowledge. We extract 43 features spanning lexical 
richness, syntactic complexity, affective tone, and hedging, and assess their impact through both Logistic Regression and 
SHAP analyses. Our findings reveal distinct stylistic profiles for each stance: favor is best detected when expressed 
concisely with minimal hedging; against when paired with strong negative emotions and greater lexical variety; and none 
when texts are lexically simple and emotionally neutral. Across classes, errors arise from excessive complexity, mixed 
emotional signals, and overuse of hedging. These results advance understanding of what drives success and failure in 
stance detection.

Understanding the Linguistic Cues Behind Stance Detection

A large body of research has examined the linguistic abilities of language models (LMs) across various languages. However, conclusive evidence regarding their semantic competence and world knowledge remains limited, especially for low-resource languages. In this study, we explore the semantic competence of Italian BabyLMs, focusing on their sensitivity to semantic violations. To this end, we adapt a minimal pair benchmark targeting semantic violations to evaluate the semantic abilities of BAMBI, a family of small-scale models trained on progressively larger and more complex datasets. We further compare their performance, assessed through accuracy, mean log-likelihood offset, and expected calibration error, with that of three larger Italian LMs. Our findings shed light on this aspect of semantic competence in small-scale models and how this is affected by data scale and training strategies.

Can a Remedy Find a Researcher? Exploring the Development of Semantic Knowledge in Italian BabyLMs

Long-context language models face efficiency challenges as context lengths expand. Traditional tokenization methods like BPE operate on frequency statistics, ignoring semantic structure and over-tokenizing redundant spans. We propose \textbf{SemToken}, a semantic-aware tokenization framework that adaptively compresses token sequences based on semantic density. SemToken uses lightweight encoders to identify and merge semantically equivalent spans, allocates variable granularity based on local semantic density, and dynamically adjusts token budgets during generation. Evaluations on WikiText-103, LongBench, and BookSum demonstrate 2.4$\times$ token reduction, 1.9$\times$ inference speedup, and 67\% memory reduction while preserving or improving model quality. SemToken integrates seamlessly with existing models and achieves multiplicative benefits when combined with FlashAttention (up to 2.7$\times$ total speedup).

SemToken: Semantic-Aware Tokenization for Efficient Long-Context Language Models

Hallucinations are a persistent challenge in natural language generation, including data-to-text. van Deemter (2024) introduced a framework based on the relation of logical consequence ("follows from"), which divides all data-to-text hallucinations into seven disjoint categories. We examine whether human annotators and large language models are able to apply the framework, in two data-to-text domains. Results suggest that the framework is applicable, although there are significant domain-dependent variations, as well as discrepancies between human and model judgments. We also uncover several issues that should inform future work on hallucination.

A Logic-Based Approach to Hallucinations in Data-to-Text NLG: Experiments with Human and LLM Annotators

Metaphors are part of everyday language and shape the way in which we conceptualize the world. Moreover, they play a multifaceted role in communication, making their understanding and generation a challenging task for language models (LMs). While there has been extensive work in the literature linking metaphor to the fulfilment of individual intentions, no comprehensive taxonomy of such intentions, suitable for natural language processing (NLP) applications, is available to present day. In this paper, we propose a novel taxonomy of intentions commonly attributed to metaphor, which comprises 9 categories. We also release the first dataset annotated for intentions behind metaphor use. Finally, we use this dataset to test the capability of large language models (LLMs) in inferring the intentions behind metaphor use, in zero- and in-context few-shot settings. Our experiments show that this is still a challenge for LLMs.

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