Nisansa de Silva’s Research Group conducts research in natural language processing with a special focus on low-resource languages such as Sinhala and Tamil, data quality in multilingual corpora, and applied machine learning, based at the Department of Computer Science & Engineering, University of Moratuwa. The group was originally established in 2011, and went on semi-hiatus while Dr. de Silva was at the University of Oregon (2014–2020). It was formally re-established in 2021 upon his return to UoM.
Faculty and students explore multiple aspects of language technology, including lexical semantics, sentiment and subjectivity analysis, graph-based NLP, and multilingual text processing. Their work has appeared at major international venues such as ACL, EACL, WMT, and LoResMT, with ongoing collaborations bridging local linguistic challenges and global research frontiers.
The group has received research funding from Google and the University of Moratuwa, while also making an impact through the release of open-source tools, surveys, and models to support the wider Sinhala and Tamil NLP communities.
PI: Nisansa de Silva
We propose to advance aspect-based sentiment analysis (ABSA) by developing enhanced models, datasets, and evaluation methods that improve the accuracy and applicability of sentiment classification across multiple domains.
PI: Nisansa de Silva
We propose to advance natural language processing for low-resource settings by leveraging data augmentation, transfer learning, and model adaptation techniques to overcome the scarcity of annotated data and linguistic resources.
PI: Nisansa de Silva
We propose to build and analyze Sinhala language resources, datasets, and models to strengthen NLP research for this low-resource language, while connecting it to English and Tamil through bilingual lexicons, embeddings, and cross-lingual methods.
PI: Rohan Samarajiva
We propose to investigate the role of natural language processing in government by building methods, frameworks, and resources that enable data-driven policy-making while ensuring ethical, transparent, and inclusive outcomes.
PI: Dejing Dou
We propose to advance methods for semantic oppositeness detection in natural language, focusing on embedding-based models and contextual representations to improve reasoning and error detection in text.
PI: Dejing Dou
We propose to advance biomedical natural language processing by combining ontology-based reasoning, semantic search, and embedding-driven methods to improve information extraction, representation, and consistency detection in biomedical texts.
Dissertations
W.A.S.A Fernando, "Data Augmentation to Induce High Quality Parallel Data for Low-Resource Neural Machine Translation", University of Moratuwa, 2025
Theses: MSc Major Component Research
Menan Velayuthan, "Multi-Domain Neural Machine Translation with Knowledge Distillation For Low Resource Languages", University of Moratuwa, 2025
Theses: MSc Minor Component Research
Pubudu Cooray, "Headline Generation for Sinhala Newspaper Articles using Pre-trained Language Models", University of Moratuwa, 2025
Dushan Kumarasinghe, "Automatic Generation of Research Paper Abstracts using Deep-Hybrid Models", University of Moratuwa, 2025
Kushan Hewapathirana, "Towards Multi-document Summarisation in Low-resource Settings", University of Moratuwa, 2025
Sadeep Gunathilaka, "Automated User Review Analysis To Facilitate Potential Mobile Application Evolution", University of Moratuwa, 2025
Journal Papers
W M Yomal De Mel and Nisansa de Silva, "Linguistic Analysis of Sinhala YouTube Comments on Sinhala Music Videos: A Dataset Study", ICTer, vol. 18, no. 2, pp. 121-130, 2025. doi: 10.4038/icter.v18i2.7299
Dineth Jayakody, A V A Malkith, Koshila Isuranda, Vishal Thenuwara, Nisansa de Silva, Sachintha Rajith Ponnamperuma, G G N Sandamali, and K L K Sudheera, "Instruct-DeBERTa: A Hybrid Approach for Aspect-based Sentiment Analysis on Textual Reviews", ICTer, vol. 18, no. 2, pp. 39-50, 2025. doi: 10.4038/icter.v18i2.7290
Conference Papers
Yomal De Mel and Nisansa de Silva, "GeeSanBhava: Sentiment Tagged Sinhala Music Video Comment Data Set", in International Conference on Computational Collective Intelligence, 2025, pp. 157--171. doi: 10.1007/978-3-032-10209-6_11
Vishal Thenuwara and Nisansa de Silva, "DESS: DeBERTa Enhanced Syntactic-Semantic Aspect Sentiment Triplet Extraction", in International Conference on Computational Collective Intelligence, 2025, pp. 185--199. doi: 10.1007/978-3-032-09318-9_13
Kasun Wickramasinghe and Nisansa de Silva, "How Good is BLI as an Alignment Measure: A Study in Word Embedding Paradigm", in International Conference on Computational Collective Intelligence, 2025, pp. 383--397. doi: 10.1007/978-3-032-10202-7_26
Imalsha Puranegedara, Themira Chathumina, Nisal Ranathunga, Nisansa de Silva, Surangika Ranathunga, and Mokanarangan Thayaparan, "Utilizing Multilingual Encoders to Improve Large Language Models for Low-Resource Languages", in Moratuwa Engineering Research Conference (MERCon), 2025. doi: 10.1109/MERCon67903.2025.11216992 
H W K Aravinda, Rashad Sirajudeen, Samith Karunathilake, Nisansa de Silva, Surangika Ranathunga, and Rishemjit Kaur, "SinLlama-A Large Language Model for Sinhala", in Moratuwa Engineering Research Conference (MERCon), 2025. doi: 10.1109/MERCon67903.2025.11217094
Aloka Fernando, Nisansa de Silva, Menan Velayuthan, Charitha Rathnayaka, and Surangika Ranathunga, "Improving the quality of Web-mined Parallel Corpora of Low-Resource Languages using Debiasing Heuristics", in Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, 2025, pp. 28252--28269. doi: 10.18653/v1/2025.emnlp-main.1435
B Karunarathne, V Nanayakkara, N de Silva, and T Ambegoda, "Equipping School Teachers with Technology: A Qualitative Study Based on a Training Program Conducted for School Teachers on Technology for Education", in EDULEARN25 Proceedings, 2025, pp. 9925--9931. doi: 10.21125/edulearn.2025.2580
Sadeep Gunathilaka and Nisansa de Silva, "Automatic Analysis of App Reviews Using LLMs", in Proceedings of the Conference on Agents and Artificial Intelligence, 2025, pp. 828-839. doi: 10.5220/0013375600003890
Yomal De Mel, Kasun Wickramasinghe, Nisansa de Silva, and Surangika Ranathunga, "Sinhala Transliteration: A Comparative Analysis Between Rule-based and Seq2Seq Approaches", in Proceedings of the First Workshop on Natural Language Processing for Indo-Aryan and Dravidian Languages, 2025, pp. 166--173.
Workshop Papers
Jayanath Senevirathna, Ayesh Vininda, Prasad Sandaruwan, Ridwan Shariffdeen, Sandareka Wickramanayake, and Nisansa de Silva, "FusionRepair: Iterative Multi-Line APR via Fusion", in IEEE/ACM International Workshop on Automated Program Repair (APR), 2025, pp. 27--34. doi: 10.1109/APR66717.2025.00009
Nethum Lamahewage, Nimantha Cooray, Ridwan Shariffdeen, Sandareka Wickramanayake, and Nisansa de Silva, "SCHOLIA-An XAI Framework for APR", in IEEE/ACM International Workshop on Automated Program Repair (APR), 2025, pp. 19--26. doi: 10.1109/APR66717.2025.00008
Nisansa de Silva, "Sinhala Diachronic Corpus", in NeurIPS 2025 AI for Science Workshop, 2025.
Menan Velayuthan, Nisansa De Silva, and Surangika Ranathunga, "Encoder-Aware Sequence-Level Knowledge Distillation for Low-Resource Neural Machine Translation", in Proceedings of the Eighth Workshop on Technologies for Machine Translation of Low-Resource Languages (LoResMT 2025), 2025, pp. 161--170.
Extended Abstracts
Kushan Hewapathirana, Nisansa de Silva, and C. D. Athuraliya, "Adapter-based Fine-tuning for PRIMERA", in 1st Applied Data Science \& Artificial Intelligence Symposium, April. 2025.
Preprints
Tyler A Chang, Catherine Arnett, Abdelrahman Eldesokey, Abdelrahman Sadallah, Abeer Kashar, Abolade Daud, Abosede Grace Olanihun, Adamu Labaran Mohammed, Adeyemi Praise, Adhikarinayum Meerajita Sharma, and others, "Global PIQA: Evaluating Physical Commonsense Reasoning Across 100+ Languages and Cultures", arXiv preprint arXiv:2510.24081, 2025
Oshadha Wijerathne, Amandi Nimasha, Dushan Fernando, Nisansa de Silva, and Srinath Perera, "ScheduleMe: Multi-Agent Calendar Assistant", arXiv preprint arXiv:2509.25693, 2025
Nevidu Jayatilleke and Nisansa de Silva, "SiDiaC: Sinhala Diachronic Corpus", arXiv preprint arXiv:2509.17912, 2025
Nevidu Jayatilleke and Nisansa de Silva, "Zero-shot OCR Accuracy of Low-Resourced Languages: A Comparative Analysis on Sinhala and Tamil", arXiv preprint arXiv:2507.18264, 2025
Kavindu Warnakulasuriya, Prabhash Dissanayake, Navindu De Silva, Stephen Cranefield, Bastin Tony Roy Savarimuthu, Surangika Ranathunga, and Nisansa de Silva, "Evolution of Cooperation in LLM-Agent Societies: A Preliminary Study Using Different Punishment Strategies", arXiv preprint arXiv:2504.19487, 2025
