ZGUL: Zero-shot Generalization to Unseen Languages using Multi-source Ensembling of Language Adapters

Vipul Rathore, Rajdeep Dhingra, Parag Singla, Mausam


Abstract
We tackle the problem of zero-shot cross-lingual transfer in NLP tasks via the use of language adapters (LAs). Most of the earlier works have explored training with adapter of a single source (often English), and testing either using the target LA or LA of another related language. Training target LA requires unlabeled data, which may not be readily available for low resource *unseen* languages: those that are neither seen by the underlying multilingual language model (e.g., mBERT), nor do we have any (labeled or unlabeled) data for them. We posit that for more effective cross-lingual transfer, instead of just one source LA, we need to leverage LAs of multiple (linguistically or geographically related) source languages, both at train and test-time - which we investigate via our novel neural architecture, ZGUL. Extensive experimentation across four language groups, covering 15 unseen target languages, demonstrates improvements of up to 3.2 average F1 points over standard fine-tuning and other strong baselines on POS tagging and NER tasks. We also extend ZGUL to settings where either (1) some unlabeled data or (2) few-shot training examples are available for the target language. We find that ZGUL continues to outperform baselines in these settings too.
Anthology ID:
2023.emnlp-main.431
Volume:
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
6969–6987
Language:
URL:
https://aclanthology.org/2023.emnlp-main.431
DOI:
10.18653/v1/2023.emnlp-main.431
Bibkey:
Cite (ACL):
Vipul Rathore, Rajdeep Dhingra, Parag Singla, and Mausam. 2023. ZGUL: Zero-shot Generalization to Unseen Languages using Multi-source Ensembling of Language Adapters. In Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing, pages 6969–6987, Singapore. Association for Computational Linguistics.
Cite (Informal):
ZGUL: Zero-shot Generalization to Unseen Languages using Multi-source Ensembling of Language Adapters (Rathore et al., EMNLP 2023)
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PDF:
https://aclanthology.org/2023.emnlp-main.431.pdf
Video:
 https://aclanthology.org/2023.emnlp-main.431.mp4