Pavel Brazdil


2023

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AfriSenti: A Twitter Sentiment Analysis Benchmark for African Languages
Shamsuddeen Muhammad | Idris Abdulmumin | Abinew Ayele | Nedjma Ousidhoum | David Adelani | Seid Yimam | Ibrahim Ahmad | Meriem Beloucif | Saif Mohammad | Sebastian Ruder | Oumaima Hourrane | Alipio Jorge | Pavel Brazdil | Felermino Ali | Davis David | Salomey Osei | Bello Shehu-Bello | Falalu Lawan | Tajuddeen Gwadabe | Samuel Rutunda | Tadesse Belay | Wendimu Messelle | Hailu Balcha | Sisay Chala | Hagos Gebremichael | Bernard Opoku | Stephen Arthur
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

Africa is home to over 2,000 languages from over six language families and has the highest linguistic diversity among all continents. This includes 75 languages with at least one million speakers each. Yet, there is little NLP research conducted on African languages. Crucial in enabling such research is the availability of high-quality annotated datasets. In this paper, we introduce AfriSenti, a sentiment analysis benchmark that contains a total of >110,000 tweets in 14 African languages (Amharic, Algerian Arabic, Hausa, Igbo, Kinyarwanda, Moroccan Arabic, Mozambican Portuguese, Nigerian Pidgin, Oromo, Swahili, Tigrinya, Twi, Xitsonga, and Yoruba) from four language families. The tweets were annotated by native speakers and used in the AfriSenti-SemEval shared task (with over 200 participants, see website: https://afrisenti-semeval.github.io). We describe the data collection methodology, annotation process, and the challenges we dealt with when curating each dataset. We further report baseline experiments conducted on the AfriSenti datasets and discuss their usefulness.

2022

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NaijaSenti: A Nigerian Twitter Sentiment Corpus for Multilingual Sentiment Analysis
Shamsuddeen Hassan Muhammad | David Ifeoluwa Adelani | Sebastian Ruder | Ibrahim Sa’id Ahmad | Idris Abdulmumin | Bello Shehu Bello | Monojit Choudhury | Chris Chinenye Emezue | Saheed Salahudeen Abdullahi | Anuoluwapo Aremu | Alípio Jorge | Pavel Brazdil
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Sentiment analysis is one of the most widely studied applications in NLP, but most work focuses on languages with large amounts of data. We introduce the first large-scale human-annotated Twitter sentiment dataset for the four most widely spoken languages in Nigeria—Hausa, Igbo, Nigerian-Pidgin, and Yorùbá—consisting of around 30,000 annotated tweets per language, including a significant fraction of code-mixed tweets. We propose text collection, filtering, processing and labeling methods that enable us to create datasets for these low-resource languages. We evaluate a range of pre-trained models and transfer strategies on the dataset. We find that language-specific models and language-adaptive fine-tuning generally perform best. We release the datasets, trained models, sentiment lexicons, and code to incentivize research on sentiment analysis in under-represented languages.

2010

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Paraphrase Alignment for Synonym Evidence Discovery
Gintarė Grigonytė | João Paulo Cordeiro | Gaël Dias | Rumen Moraliyski | Pavel Brazdil
Proceedings of the 23rd International Conference on Computational Linguistics (Coling 2010)

2009

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Unsupervised Induction of Sentence Compression Rules
João Cordeiro | Gaël Dias | Pavel Brazdil
Proceedings of the 2009 Workshop on Language Generation and Summarisation (UCNLG+Sum 2009)