NGLUEni: Benchmarking and Adapting Pretrained Language Models for Nguni Languages

Francois Meyer, Haiyue Song, Abhisek Chakrabarty, Jan Buys, Raj Dabre, Hideki Tanaka


Abstract
The Nguni languages have over 20 million home language speakers in South Africa. There has been considerable growth in the datasets for Nguni languages, but so far no analysis of the performance of NLP models for these languages has been reported across languages and tasks. In this paper we study pretrained language models for the 4 Nguni languages - isiXhosa, isiZulu, isiNdebele, and Siswati. We compile publicly available datasets for natural language understanding and generation, spanning 6 tasks and 11 datasets. This benchmark, which we call NGLUEni, is the first centralised evaluation suite for the Nguni languages, allowing us to systematically evaluate the Nguni-language capabilities of pretrained language models (PLMs). Besides evaluating existing PLMs, we develop new PLMs for the Nguni languages through multilingual adaptive finetuning. Our models, Nguni-XLMR and Nguni-ByT5, outperform their base models and large-scale adapted models, showing that performance gains are obtainable through limited language group-based adaptation. We also perform experiments on cross-lingual transfer and machine translation. Our models achieve notable cross-lingual transfer improvements in the lower resourced Nguni languages (isiNdebele and Siswati). To facilitate future use of NGLUEni as a standardised evaluation suite for the Nguni languages, we create a web portal to access the collection of datasets and publicly release our models.
Anthology ID:
2024.lrec-main.1071
Volume:
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
Month:
May
Year:
2024
Address:
Torino, Italia
Editors:
Nicoletta Calzolari, Min-Yen Kan, Veronique Hoste, Alessandro Lenci, Sakriani Sakti, Nianwen Xue
Venues:
LREC | COLING
SIG:
Publisher:
ELRA and ICCL
Note:
Pages:
12247–12258
Language:
URL:
https://aclanthology.org/2024.lrec-main.1071
DOI:
Bibkey:
Cite (ACL):
Francois Meyer, Haiyue Song, Abhisek Chakrabarty, Jan Buys, Raj Dabre, and Hideki Tanaka. 2024. NGLUEni: Benchmarking and Adapting Pretrained Language Models for Nguni Languages. In Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024), pages 12247–12258, Torino, Italia. ELRA and ICCL.
Cite (Informal):
NGLUEni: Benchmarking and Adapting Pretrained Language Models for Nguni Languages (Meyer et al., LREC-COLING 2024)
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PDF:
https://preview.aclanthology.org/landing_page/2024.lrec-main.1071.pdf