Data Augmentation for Machine Translation via Dependency Subtree Swapping
This work addresses data scarcity for machine translation practitioners, but it is incremental as it builds on existing augmentation techniques.
The paper tackles the problem of limited training data for machine translation by proposing a data augmentation framework using dependency subtree swapping, which improved BLEU scores in 3 out of 4 language pairs tested.
We present a generic framework for data augmentation via dependency subtree swapping that is applicable to machine translation. We extract corresponding subtrees from the dependency parse trees of the source and target sentences and swap these across bisentences to create augmented samples. We perform thorough filtering based on graphbased similarities of the dependency trees and additional heuristics to ensure that extracted subtrees correspond to the same meaning. We conduct resource-constrained experiments on 4 language pairs in both directions using the IWSLT text translation datasets and the Hunglish2 corpus. The results demonstrate consistent improvements in BLEU score over our baseline models in 3 out of 4 language pairs. Our code is available on GitHub.