The Automatic Speech Recognition (ASR) has come up with significant advancements over the course of several decades, transitioning from a rule-based method to a statistical approach, and ultimately to the use of end-to-end (E2E) frameworks. This phenomenon continues with the progression of machine learning and deep learning methodologies. The E2E approach for ASR has demonstrated predominant success in the case of resourceful languages with larger annotated corpus. However, the accuracy is quite low for low-resourced languages such as Nepali. In this regard, language-specific tools such as tokenizers seem to play a vital role in improving the performance of the E2E model for low-resourced languages like Nepali. In this paper, we propose a pronunciationaware syllable tokenizer for the Nepali language which improves the results of the E2E model. Our experiment confirm that the introduction of the proposed tokenizer yields better performance with the Character Error Rate (CER) 8.09% compared to other language-independent tokenizers.

Fine tuning of the pre-trained language model is a technique which can be used to enhance the technologies of low-resourced languages. The unsupervised approach can fine-tune any pre-trained model with minimum or even no language-specific resources. It is highly advantageous, particularly for languages that possess limited computational resources. We present a novel approach for fine-tuning a pre-trained Automatic Speech Recognition (ASR) model that is suitable for low resource languages. Our methods involves iterative fine-tuning of pre-trained ASR model. mms-1b is selected as the pretrained seed model for fine-tuning. We take the Nepali language as a case study for this research work. Our approach achieved a CER of 6.77%, outperforming all previously recorded CER values for the Nepali ASR Systems.

Research on Deep learning-based Text-toSpeech (TTS) systems has gained increasing popularity in low-resource languages as this approach is not only computationally robust but also has the capability to produce state-ofthe-art results. However, these approaches are yet to be significantly explored for the Nepali language, primarily because of the lack of adequate size datasets and secondarily because of the relatively sophisticated computing resources they demand. This paper explores the FastPitch acoustic model with HiFi-GAN vocoder for the Nepali language. We trained the acoustic model with two datasets, OpenSLR and a dataset prepared jointly by the Information and Language Processing Research Lab (ILPRL) and the Nepal Association of the Blind (NAB), to be further referred to as the ILPRLNAB dataset. We achieved a Mean Opinion Score (MOS) of 3.70 and 3.40 respectively for the same model with different datasets. The synthesized speech produced by the model was found to be quite natural and of good quality.