Improving Accuracy of Low-resource ASR using Rule-Based Character Constituency Loss (RBCCL)

@inproceedings{ghimire-etal-2025-improving,
    title = "Improving Accuracy of Low-resource {ASR} using Rule-Based Character Constituency Loss ({RBCCL})",
    author = "Ghimire, Rupak Raj  and
      Poudyal, Prakash  and
      Bal, Bal Krishna",
    editor = "Sarveswaran, Kengatharaiyer  and
      Vaidya, Ashwini  and
      Krishna Bal, Bal  and
      Shams, Sana  and
      Thapa, Surendrabikram",
    booktitle = "Proceedings of the First Workshop on Challenges in Processing South Asian Languages (CHiPSAL 2025)",
    month = jan,
    year = "2025",
    address = "Abu Dhabi, UAE",
    publisher = "International Committee on Computational Linguistics",
    url = "https://aclanthology.org/2025.chipsal-1.6/",
    pages = "61--70",
    abstract = "Modern general-purpose speech recognition systems are more robust in languages with high resources. However, achieving state-of-the-art accuracy for low-resource languages is still challenging. To deal with this challenge, one of the popular practice is fine-tuning the pre-trained model on low-resource settings. Nevertheless, pre-trained or fine-tuned model fails to capture the complex character and word constituency in the Devanagari script transcription. We proposed a complementary loss function designed to force the model to learn the character constituency of Devanagari script. Our complementary loss function, called as Rule-Based Character Constituency Loss (RBCCL), that penalizes incorrect transcriptions and updates the overall loss during the model training phase. This loss function can be combined with CTC loss or cross-entropy loss as well which are widely used in ASR training. Our experiment shows that combining the existing cross-entropy loss with new complementary loss (RBCCL) improves the Word Error Rate (WER ), reducing it from 47.1{\%} to 23.41{\%} which is quite promising result."
}