Investigating Lexical Replacements for Arabic-English Code-Switched Data Augmentation
This work addresses data scarcity for code-switching NLP systems, particularly in dialectal Arabic-English contexts, with incremental improvements over existing methods.
The paper tackles data sparsity in Arabic-English code-switching NLP by investigating lexical replacement techniques for data augmentation, resulting in improvements such as a 34% reduction in perplexity, 5.2% relative WER improvement for ASR, and up to 5.1 BLEU points gain for MT.
Data sparsity is a main problem hindering the development of code-switching (CS) NLP systems. In this paper, we investigate data augmentation techniques for synthesizing dialectal Arabic-English CS text. We perform lexical replacements using word-aligned parallel corpora where CS points are either randomly chosen or learnt using a sequence-to-sequence model. We compare these approaches against dictionary-based replacements. We assess the quality of the generated sentences through human evaluation and evaluate the effectiveness of data augmentation on machine translation (MT), automatic speech recognition (ASR), and speech translation (ST) tasks. Results show that using a predictive model results in more natural CS sentences compared to the random approach, as reported in human judgements. In the downstream tasks, despite the random approach generating more data, both approaches perform equally (outperforming dictionary-based replacements). Overall, data augmentation achieves 34% improvement in perplexity, 5.2% relative improvement on WER for ASR task, +4.0-5.1 BLEU points on MT task, and +2.1-2.2 BLEU points on ST over a baseline trained on available data without augmentation.