Nafiseh Nikeghbal
Author directory2026
Computationally Invisible: Charting the NLP Landscape of Iranic Languages
Hojjat Mokhtarabadi | Amir Hossein Kargaran | Ali Shakeri | Saba Shafiei | Nafiseh Nikeghbal | Mohammad Hossein Manshaei
Findings of the Association for Computational Linguistics: EMNLP 2026
Hojjat Mokhtarabadi | Amir Hossein Kargaran | Ali Shakeri | Saba Shafiei | Nafiseh Nikeghbal | Mohammad Hossein Manshaei
Findings of the Association for Computational Linguistics: EMNLP 2026
The Iranic language family spans 101 ISO 639-3 coded varieties and over 200 million speakers across a vast arc from the Caucasus through the Middle East and Central Asia to South Asia and China. Yet this richness is barely reflected in modern NLP: resources, models, and benchmarks are overwhelmingly concentrated on Iranian Persian, leaving Kurdish, Pashto, Balochi, Gilaki, Zazaki, and the Pamir languages computationally invisible. This survey provides the first comprehensive landscape analysis of Iranic NLP, covering 495 papers published between 2020 and early 2026. We examine language coverage, NLP tasks, datasets, modeling approaches, and evaluation practices, and identify persistent structural gaps: script heterogeneity, dialectal fragmentation, data scarcity, and an evaluation monoculture that has saturated Persian while leaving near-zero baselines for every other variety. Together with this survey, we release a companion website providing interactive language maps, a curated resource browser, and a live publication index at https://sigiranic.github.io.
Who Flips? Self- and Cross-Model Counterarguments Reveal Answer Instability in LLMs
Nafiseh Nikeghbal | Amir Hossein Kargaran | Shaghayegh Kolli | Jana Diesner
Findings of the Association for Computational Linguistics: EMNLP 2026
Nafiseh Nikeghbal | Amir Hossein Kargaran | Shaghayegh Kolli | Jana Diesner
Findings of the Association for Computational Linguistics: EMNLP 2026
Standard accuracy benchmarks evaluate whether large language models (LLMs) reach correct answers. However, they do not test whether models maintain that answer when challenged by a plausible counter-argument. We introduce a controlled protocol for evaluating answer stability: after a model answers a multiple-choice question correctly, we challenge the model’s answer with a coherent argument for an incorrect option and measure whether the model flips. The setup a) isolates argumentative content from overt social pressure and b) varies argument length, self-attribution, and cross-model source. Across seven frontier models and 57 MMLU subjects, flip rates range from 17.5% to 97.3%, revealing large differences in stability that are not captured by accuracy metrics alone. We find that self-attribution consistently increases flip rates (mean +7.1pp, up to +18.7pp). Furthermore, pooling wrong-answer arguments across models and selecting the most effective one per question yields stronger adversarial challenges than relying on any single source model. From this cross-model pool, we construct MaxFlip, a curated benchmark that amplifies answer flips by up to +23.6pp over self-generated challenges. We release the protocol, challenge records, and MaxFlip to support stability evaluation alongside standard accuracy benchmarks. Materials are available at https://github.com/nafisenik/WhoFlips, https://hf.co/datasets/nafisehNik/WhoFlips.
2025
MEXA: Multilingual Evaluation of English-Centric LLMs via Cross-Lingual Alignment
Amir Hossein Kargaran | Ali Modarressi | Nafiseh Nikeghbal | Jana Diesner | François Yvon | Hinrich Schuetze
Findings of the Association for Computational Linguistics: ACL 2025
Amir Hossein Kargaran | Ali Modarressi | Nafiseh Nikeghbal | Jana Diesner | François Yvon | Hinrich Schuetze
Findings of the Association for Computational Linguistics: ACL 2025
English-centric large language models (LLMs) often show strong multilingual capabilities. However, their multilingual performance remains unclear and is under-evaluated for many other languages. Most benchmarks for multilinguality focus on classic NLP tasks or cover a minimal number of languages. We introduce MEXA, a method for assessing the multilingual capabilities of pre-trained English-centric LLMs using parallel sentences, which are available for more languages than existing downstream tasks. MEXA leverages that English-centric LLMs use English as a pivot language in their intermediate layers. MEXA computes the alignment between English and non-English languages using parallel sentences to evaluate the transfer of language understanding from English to other languages. This alignment can be used to estimate model performance in different languages. We conduct controlled experiments using various parallel datasets (FLORES-200 and Bible), models (Llama family, Gemma family, Mistral, and OLMo), and established downstream tasks (Belebele, m-MMLU, and m-ARC). We explore different methods to compute embeddings in decoder-only models. Our results show that MEXA, in its default settings, achieves an average Pearson correlation of 0.90 between its predicted scores and actual task performance across languages. This suggests that MEXA is a reliable method for estimating the multilingual capabilities of English-centric LLMs, providing a clearer understanding of their multilingual potential and the inner workings of LLMs. Leaderboard: https://cis-lmu-mexa.hf.space, Code: https://github.com/cisnlp/MEXA.
CoBia: Constructed Conversations Can Trigger Otherwise Concealed Societal Biases in LLMs
Nafiseh Nikeghbal | Amir Hossein Kargaran | Jana Diesner
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Nafiseh Nikeghbal | Amir Hossein Kargaran | Jana Diesner
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Improvements in model construction, including fortified safety guardrails, allow Large language models (LLMs) to increasingly pass standard safety checks. However, LLMs sometimes slip into revealing harmful behavior, such as expressing racist viewpoints, during conversations. To analyze this systematically, we introduce CoBia, a suite of lightweight adversarial attacks that allow us to refine the scope of conditions under which LLMs depart from normative or ethical behavior in conversations. CoBia creates a constructed conversation where the model utters a biased claim about a social group. We then evaluate whether the model can recover from the fabricated bias claim and reject biased follow-up questions.We evaluate 11 open-source as well as proprietary LLMs for their outputs related to six socio-demographic categories that are relevant to individual safety and fair treatment, i.e., gender, race, religion, nationality, sex orientation, and others. Our evaluation is based on established LLM-based bias metrics, and we compare the results against human judgments to scope out the LLMs’ reliability and alignment. The results suggest that purposefully constructed conversations reliably reveal bias amplification and that LLMs often fail to reject biased follow-up questions during dialogue. This form of stress-testing highlights deeply embedded biases that can be surfaced through interaction. Code and artifacts are available at https://github.com/nafisenik/CoBia.