Randil Pushpananda


2025

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Towards Effective Emotion Analysis in Low-Resource Tamil Texts
Priyatharshan Balachandran | Uthayasanker Thayasivam | Randil Pushpananda | Ruvan Weerasinghe
Proceedings of the Fifth Workshop on Speech, Vision, and Language Technologies for Dravidian Languages

Emotion analysis plays a significant role in understanding human behavior and communication, yet research in Tamil language remains limited. This study focuses on building an emotion classifier for Tamil texts using machine learning (ML) and deep learning (DL), along with creating an emotion-annotated Tamil corpus for Ekman’s basic emotions. Our dataset combines publicly available data with re-annotation and translations. Along with traditional ML models we investigated the use of Transfer Learning (TL) with state-of-the-art models, such as BERT and Electra based models. Experiments were conducted on unbalanced and balanced datasets using data augmentation techniques. The results indicate that MultinomialNaive Bayes (MNB) and Support Vector Machine (SVM) performed well with TF-IDF and BoW representations, while among Transfer Learning models, LaBSE achieved the highest accuracy (63% balanced, 69% unbalanced), followed by TamilBERT and IndicBERT.

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SinhalaMMLU: A Comprehensive Benchmark for Evaluating Multitask Language Understanding in Sinhala
Ashmari Pramodya | Nirasha Nelki | Heshan Shalinda | Chamila Liyanage | Yusuke Sakai | Randil Pushpananda | Ruvan Weerasinghe | Hidetaka Kamigaito | Taro Watanabe
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

Large Language Models (LLMs) demonstrate impressive general knowledge and reasoning abilities, yet their evaluation has predominantly focused on global or anglocentric subjects, often neglecting low-resource languages and culturally specific content. While recent multilingual benchmarks attempt to bridge this gap, many rely on automatic translation, which can introduce errors and misrepresent the original cultural context. To address this, we introduce SinhalaMMLU, the first multiple-choice question answering benchmark designed specifically for Sinhala, a low-resource language. The dataset includes over 7,000 questions spanning secondary to collegiate education levels, aligned with the Sri Lankan national curriculum, and covers six domains and 30 subjects, encompassing both general academic topics and culturally grounded knowledge. We evaluate 26 LLMs on SinhalaMMLU and observe that, while Claude 3.5 sonnet and GPT-4o achieve the highest average accuracies at 67% and 62% respectively, overall model performance remains limited. In particular, models struggle in culturally rich domains such as the Humanities, revealing substantial room for improvement in adapting LLMs to low-resource and culturally specific contexts.

2024

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Developing a Sandhi Lexicon (SandhiLex) for Sinhala: Understanding and Formalizing Morphophonology of Sinhala Language
Chamila Liyanage | Randil Pushpananda
Proceedings of the 38th Pacific Asia Conference on Language, Information and Computation

2023

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Sinhala Dependency Treebank (STB)
Chamila Liyanage | Kengatharaiyer Sarveswaran | Thilini Nadungodage | Randil Pushpananda
Proceedings of the Sixth Workshop on Universal Dependencies (UDW, GURT/SyntaxFest 2023)

This paper reports the development of the first dependency treebank for the Sinhala language (STB). Sinhala, which is morphologically rich, is a low-resource language with few linguistic and computational resources available publicly. This treebank consists of 100 sentences taken from a large contemporary written text corpus. These sentences were annotated manually according to the Universal Dependencies framework. In this paper, apart from elaborating on the approach that has been followed to create the treebank, we have also discussed some interesting syntactic constructions found in the corpus and how we have handled them using the current Universal Dependencies specification.

2021

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Improve Sinhala Speech Recognition Through e2e LF-MMI Model
Buddhi Gamage | Randil Pushpananda | Thilini Nadungodage | Ruwan Weerasinghe
Proceedings of the 18th International Conference on Natural Language Processing (ICON)

Automatic speech recognition (ASR) has experienced several paradigm shifts over the years from template-based approaches and statistical modeling to the popular GMM-HMM approach and then to deep learning hybrid model DNN-HMM. The latest shift is to end-to-end (e2e) DNN architecture. We present a study to build an e2e ASR system using state-of-the-art deep learning models to verify the applicability of e2e ASR models for the highly inflected and yet low-resource Sinhala language. We experimented on e2e Lattice-Free Maximum Mutual Information (e2e LF-MMI) model with the baseline statistical models with 40 hours of training data to evaluate. We used the same corpus for creating language models and lexicon in our previous study, which resulted in the best accuracy for the Sinhala language. We were able to achieve a Word-error-rate (WER) of 28.55% for Sinhala, only slightly worse than the existing best hybrid model. Our model, however, is more context-independent and faster for Sinhala speech recognition and so more suitable for general purpose speech-to-text translation.

2014

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Sinhala-Tamil Machine Translation: Towards better Translation Quality
Randil Pushpananda | Ruvan Weerasinghe | Mahesan Niranjan
Proceedings of the Australasian Language Technology Association Workshop 2014