Constrained density matching and modeling for cross-lingual alignment of contextualized representations


Multilingual representations pre-trained with monolingual data exhibit considerably unequal task performances across languages. Previous studies address this challenge with resource-intensive contextualized alignment, which assumes the availability of large parallel data, thereby leaving under-represented language communities behind. In this work, we attribute the data hungriness of previous alignment techniques to two limitations: (i) the inability to sufficiently leverage data and (ii) these techniques are not trained properly. To address these issues, we introduce supervised and unsupervised density-based approaches named Real-NVP and GAN-Real-NVP, driven by Normalizing Flow, to perform alignment, both dissecting the alignment of multilingual subspaces into density matching and density modeling. We complement these approaches with our validation criteria in order to guide the training process. Our experiments encompass 16 alignments, including our approaches, evaluated across 6 language pairs, synthetic data and 5 NLP tasks. We demonstrate the effectiveness of our approaches in the scenarios of limited and no parallel data. First, our supervised approach trained on 20k parallel data (sentences) mostly surpasses Joint-Align and InfoXLM trained on over 100k parallel sentences. Second, parallel data can be removed without sacrificing performance when integrating our unsupervised approach in our bootstrapping procedure, which is theoretically motivated to enforce equality of multilingual subspaces. Moreover, we demonstrate the advantages of validation criteria over validation data for guiding supervised training.


DOI: 10.48550/arXiv.2201.13429

Research Groups: Natural Language Processing

Publication type: InProceedings

Citation: Proceedings of Machine Learning Research, 2022. Asian Conference on Machine Leaning, Hyderabad, India, 12-14 December 2022

Date Published: 12th Dec 2022


Registered Mode: manually

Authors: Wei Zhao, Steffen Eger

help Submitter
Zhao, W., & Eger, S. (2022). Constrained Density Matching and Modeling for Cross-lingual Alignment of Contextualized Representations (Version 2). arXiv.

Views: 1913

Created: 8th Feb 2023 at 15:52

Last updated: 5th Mar 2024 at 21:25

help Tags

This item has not yet been tagged.

help Attributions


Powered by
Copyright © 2008 - 2023 The University of Manchester and HITS gGmbH