Why Does Zero-Shot Cross-Lingual Generation Fail? An Explanation and a Solution

Tianjian Li, Kenton Murray


Abstract
Zero-shot cross-lingual transfer is when a multilingual model is trained to perform a task in one language and then is applied to another language. Although the zero-shot cross-lingual transfer approach has achieved success in various classification tasks, its performance on natural language generation tasks falls short in quality and sometimes outputs an incorrect language. In our study, we show that the fine-tuning process learns language invariant representations, which is beneficial for classification tasks but harmful for generation tasks. Motivated by this, we propose a simple method to regularize the model from learning language invariant representations and a method to select model checkpoints without a development set in the target language, both resulting in better generation quality. Experiments on three semantically diverse generation tasks show that our method reduces the accidental translation problem by 68% and improves the ROUGE-L score by 1.5 on average.
Anthology ID:
2023.findings-acl.789
Volume:
Findings of the Association for Computational Linguistics: ACL 2023
Month:
July
Year:
2023
Address:
Toronto, Canada
Editors:
Anna Rogers, Jordan Boyd-Graber, Naoaki Okazaki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
12461–12476
Language:
URL:
https://aclanthology.org/2023.findings-acl.789
DOI:
10.18653/v1/2023.findings-acl.789
Bibkey:
Cite (ACL):
Tianjian Li and Kenton Murray. 2023. Why Does Zero-Shot Cross-Lingual Generation Fail? An Explanation and a Solution. In Findings of the Association for Computational Linguistics: ACL 2023, pages 12461–12476, Toronto, Canada. Association for Computational Linguistics.
Cite (Informal):
Why Does Zero-Shot Cross-Lingual Generation Fail? An Explanation and a Solution (Li & Murray, Findings 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.findings-acl.789.pdf
Video:
 https://aclanthology.org/2023.findings-acl.789.mp4