India

Vision-language Models (VLMs) have made significant strides in visual understanding and query response generation, but often face challenges of high computational cost and inference latency due to autoregressive decoding. In this work, we introduce an imitation-learning-based Self-Speculative Decoding (SSD) framework, named FastVLM, to address these limitations. Our approach employs a lightweight draft model for token generation in an autoregressive manner, while a full model verifies these tokens non-autoregressively. Accepted tokens proceed seamlessly, while rejected tokens are corrected by the full model and used to guide the draft model’s refinement. Through an imitation network, FastVLM enhances the draft model by integrating deeper-level insights from the full model&#39;s architecture. Also, it maintains the performance integrity of the full model while training the draft model, achieving a balance between efficiency and accuracy. Our method speeds up the inference process by $1.55-1.85\times$ as compared to the final layer with minimal loss in performance. The source code is available at https://github.com/Div290/SSD.

IJCNLP-AACL 2025

FastVLM: Self-Speculative Decoding for Fast Vision-Language Model Inference

self-speculative decoding

latency reduction

efficient inference

Vision-language Models (VLMs) have made significant strides in visual understanding and query response generation, but often face challenges of high computational cost and inference latency due to autoregressive decoding. In this work, we introduce an imitation-learning-based Self-Speculative Decoding (SSD) framework, named FastVLM, to address these limitations. Our approach employs a lightweight draft model for token generation in an autoregressive manner, while a full model verifies these tokens non-autoregressively. Accepted tokens proceed seamlessly, while rejected tokens are corrected by the full model and used to guide the draft model’s refinement. Through an imitation network, FastVLM enhances the draft model by integrating deeper-level insights from the full model's architecture. Also, it maintains the performance integrity of the full model while training the draft model, achieving a balance between efficiency and accuracy. Our method speeds up the inference process by $1.55-1.85\times$ as compared to the final layer with minimal loss in performance. The source code is available at https://github.com/Div290/SSD.

### Welcome to IJCNLP-AACL 2025! 
 It is a great honor to host this joint conference in Mumbai, India, from December 20 to 24, 2025. The joint conferences of IJCNLP and AACL are organized with alternating leadership in the Asia-Pacific region. The event is run by the Asian Federation of Natural Language Processing (AFNLP) in odd years, and by AACL in even years, while it is organized solely by ACL when the annual ACL meeting is held in the region. This year, the conference is primarily organized by AFNLP. 
*Kentaro Inui
MBZUAI, UAE
General Chair, IJCNLP-AACL 2025* 
Read full message and download the Conference Handbook [**here**](https://drive.google.com/file/d/1UTwxkAqSqI-GAoJC3wE1zZt5VP1Y8GX0/view?usp=sharing).

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The 14th IJCNLP & 4th AACL will be held in Mumbai, India from December 20th to December 24th, 2025.

In the deployment of Large Language Models (LLMs), ``spurious correctness''---where answers are correct but reasoning contains errors---poses a critical risk by creating an illusion of reliability. While prior work on LLM confidence estimation focuses on answer-level or entire reasoning path confidence, these coarse-grained approaches fail to identify which specific parts of the reasoning contain errors. We propose a fine-grained confidence estimation framework that computes confidence scores for individual evidence triplets within reasoning chains, enabling precise localization of errors. Using carefully designed prompts, we generate answers, evidence in triplet format, and their respective confidence scores simultaneously, allowing automatic detection of spurious correctness patterns where partial evidence contains factual errors. Evaluated on both Japanese and English multi-hop QA benchmarks across multiple models from three model families representing different architectures and training approaches, we show that our approach exhibits superior calibration performance for evidence confidence and demonstrates effective ability to detect spurious correct answers (up to 0.84 on our primary discrimination metric). The consistent improvements across languages demonstrate the generalizability of our method. As a secondary benefit, joint generation of confidence scores improves answer confidence calibration by up to 43\%. This prompt-based approach requires no model retraining and is immediately applicable to existing LLMs.

Fine-grained Confidence Estimation for Spurious Correctness Detection in Large Language Models

Multilingual generation with large language models (LLMs) is often of poor quality for mid- to low-resource languages, but the causes for this are not well-understood. We first demonstrate the existence of an implicit task-solving→translation pipeline for generation, whereby the model first solves the required task in a largely target-language-agnostic manner, and subsequently translates answer concepts into the intended target language. We hypothesize that the failure of the translation stage, despite task-solving success, is an important culprit for the observed low quality of final outputs, and formalize this as the translation barrier hypothesis. We quantify the extent to which either stage in the pipeline is responsible for final failure for a word translation task across 108 language pairs, and find that the translation barrier explains a dominant portion of error for a majority of language pairs, and is especially severe for low-resource target languages. Our results highlight an important bottleneck for end-to-end multilingual generation, relevant for future work seeking to improve multilinguality in LLMs.

The Translation Barrier Hypothesis: Multilingual Generation with Large Language Models Suffers from Implicit Translation Failure

Pruning techniques have been studied to construct small models for efficiency, yet the effect of cross-lingual, which shows language performance transferability, is understudied in this field. In this work, we investigate cross-lingual effects in multilingual large language model compression using iterative pruning and recovery. We employ structured layer pruning with LoRA-based recovery and knowledge distillation, testing whether calibration languages different from target evaluation languages can preserve multilingual performance. Experiments on Qwen2.5-7B and Llama3.1-8B demonstrate that any recovery language consistently outperforms no-recovery baselines, with even low-resource languages like Swahili providing ~5% improvements. In contrast to expectations, dominant pretraining languages do not always yield the best results, where Indonesian achieves the highest performance in Llama3.1-8B, while Japanese performs the best in Qwen2.5-7B. Our findings reveal that cross-lingual calibration effectively maintains multilingual capabilities in the iterative pruning.

Multilingual Iterative Model Pruning: What Matters?

Mining parallel document pairs for document-level machine translation (MT) remains challenging due to the limitations of existing Cross-Lingual Document Alignment (CLDA) techniques. Existing methods often rely on metadata such as URLs, which are scarce, or on pooled document representations that fail to capture fine-grained alignment cues. Moreover, the limited context window of sentence embedding models hinders their ability to represent document-level context, while sentence-based alignment introduces a combinatorially large search space, leading to high computational cost. To address these challenges for Indic languages, we introduce Pralekha, a benchmark containing over 3 million aligned document pairs across 11 Indic languages and English, which includes 1.5 million English–Indic pairs. Furthermore, we propose Document Alignment Coefficient (DAC), a novel metric for fine-grained document alignment. Unlike pooling-based methods, DAC aligns documents by matching smaller chunks and computes similarity as the ratio of aligned chunks to the average number of chunks in a pair. Intrinsic evaluation shows that our chunk-based method is 2–3× faster while maintaining competitive performance, and that DAC achieves substantial gains over pooling-based baselines. Extrinsic evaluation further demonstrates that document-level MT models trained on DAC-aligned pairs consistently outperform those using baseline alignment methods. These results highlight DAC’s effectiveness for parallel document mining. The dataset and evaluation framework are publicly available to support further research.

PRALEKHA: Cross-Lingual Document Alignment for Indic Languages

We explore whether synthetic datasets generated by large language models using a few high quality seed samples are useful for low-resource named entity recognition, considering 11 languages from three language families. Our results suggest that synthetic data created with such seed data is a reasonable choice when there is no available labeled data, and is better than using entirely automatically labeled data. However, a small amount of high-quality data, coupled with cross-lingual transfer from a related language, always offers better performance. Data and code available at: https://github.com/grvkamath/low-resource-syn-ner.

Does Synthetic Data Help Named Entity Recognition for Low-Resource Languages?

Language model architectures are predominately first created for English and afterwards applied to other languages. This can lead to problems for languages that are structurally different from English. We study one specific architectural choice: positional encodings. We do this through the lens of the trade-off hypothesis: the supposed interplay between morphological complexity and word order flexibility. This hypothesis states there exists a trade-off between the two: a more morphologically complex language can have a more flexible word order, and vice-versa. Positional encodings are a direct target to investigate the implications of this hypothesis in relation to language modelling. We pre-train and evaluate three monolingual model variants with absolute, relative and no position encodings for seven typologically diverse languages and evaluate on four downstream tasks. We fail to find a consistent trend with various proxies for morphological complexity and word order flexibility. Our work shows choice of tasks, languages, and metrics are essential for drawing stable conclusions.

On the Interplay between Positional Encodings, Morphological Complexity, and Word Order Flexibility

Despite remarkable advances in natural language processing, developing effective systems for low-resource languages remains a formidable challenge, with performances typically lagging far behind high-resource counterparts due to data scarcity and insufficient linguistic resources. Cross-lingual knowledge transfer has emerged as a promising approach to address this challenge by leveraging resources from high-resource languages. In this paper, we investigate methods for transferring linguistic knowledge from high-resource languages to low-resource languages, where the number of labeled training instances is in hundreds. We focus on sentence-level and word-level tasks. We introduce a novel method, GETR (Graph-Enhanced Token Representation) for cross-lingual knowledge transfer along with two adopted baselines (a) augmentation in hidden layers and (b) token embedding transfer through token translation. Experimental results demonstrate that our GNN-based approach significantly outperforms existing multilingual and cross-lingual baseline methods, achieving 13 percentage point improvements on truly low-resource languages (Mizo, Khasi) for POS tagging, and 20 and 27 percentage point improvements in macro-F1 on simulated low-resource languages (Marathi, Bangla, Malayalam) across sentiment classification and NER tasks respectively. We also present a detailed analysis of the transfer mechanisms and identify key factors that contribute to successful knowledge transfer in this linguistic context.

BhashaSetu: Cross-Lingual Knowledge Transfer from High-Resource to Extreme Low-Resource Languages

In recent years, machine translation has evolved with the integration of multimodal information. Infusion of multi-modality into translation tasks decreases ambiguation and enhances translation scores. Common modalities include images, speech, and videos, which provide additional context alongside the text to be translated. While multimodal translation with images has been extensively studied, video-guided machine translation (VMT) has gained increasing attention, particularly since Wang et al. 2019 first explored this task. In this paper, we provide a comprehensive overview of VMT, highlighting its unique challenges, methodologies, and recent advancements. Unlike previous surveys that primarily focus on image-guided multimodal machine translation, this work explores the distinct complexities and opportunities introduced by adding video as a modality to the translation task.

Video-guided Machine Translation: A Survey of Models, Datasets, and Challenges

Temporal reasoning and knowledge are essential capabilities for language models (LMs).
While much prior work has analyzed and improved temporal reasoning in LMs, most studies have focused solely on the Gregorian calendar.
However, many non-Gregorian systems, such as the Japanese, Hijri, and Hebrew calendars, are in active use and reflect culturally grounded conceptions of time.
If and how well current LMs can accurately handle such non-Gregorian calendars has not been evaluated so far.
Here, we present a systematic evaluation of how well language models handle one such non-Gregorian system: the Japanese *wareki*.
We create datasets that require temporal knowledge and reasoning in using *wareki* dates. 
Evaluating open and closed LMs, we find that some models can perform calendar conversions, but GPT-4o, Deepseek V3, and even Japanese-centric models struggle with Japanese calendar arithmetic and knowledge involving *wareki* dates.
Error analysis suggests corpus frequency of Japanese calendar expressions and a Gregorian bias in the model's knowledge as possible explanations.
Our results show the importance of developing LMs that are better equipped for culture-specific tasks such as calendar understanding.

Can Language Models Handle a Non-Gregorian Calendar? The Case of the Japanese wareki

Large language models (LLMs) provide detailed and impressive responses to queries in English. However, are they really consistent at responding to the same query in other languages? The popular way of evaluating for multilingual performance of LLMs requires expensive-to-collect annotated datasets. Further, evaluating for tasks like open-ended generation, where multiple correct answers may exist, is nontrivial. Instead, we propose to evaluate the predictability of model response across different languages. In this work, we propose a framework to evaluate LLM's cross-lingual consistency based on a simple Translate then Evaluate strategy. We instantiate this evaluation framework along two dimensions of consistency: information and empathy. Our results reveal pronounced inconsistencies in popular LLM responses across thirty languages, with severe performance deficits in certain language families and scripts, underscoring critical weaknesses in their multilingual capabilities. These findings necessitate cross-lingual evaluations that are consistent along multiple dimensions. We invite practitioners to use our framework for future multilingual LLM benchmarking.

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Fine-grained Confidence Estimation for Spurious Correctness Detection in Large Language Models

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