# Code-Switched Urdu ASR for Noisy Telephonic Environment using Data Centric Approach with Hybrid HMM and CNN-TDNN

arXiv: https://arxiv.org/abs/2307.12759 · HTML: https://mlsanity.com/paper/2307.12759/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- Builds on 6 of its 74 references that are in the map.
- First posted on arXiv 24 Jul 2023.

## Builds on (most cited first, 6 of 6)

- [Neural Architecture Search For LF-MMI Trained Time Delay Neural Networks](https://mlsanity.com/paper/2201.03943/) (2022)
- [Semi-supervised acoustic model training for five-lingual code-switched ASR](https://mlsanity.com/paper/1906.08647/) (2019)
- [Continual Learning for Monolingual End-to-End Automatic Speech Recognition](https://mlsanity.com/paper/2112.09427/) (2021)
- [An Investigation into the Effectiveness of Enhancement in ASR Training and Test for CHiME-5 Dinner Party Transcription](https://mlsanity.com/paper/1909.12208/) (2019)
- [Improved TDNNs using Deep Kernels and Frequency Dependent Grid-RNNs](https://mlsanity.com/paper/1802.06412/) (2018)
- [PronouncUR: An Urdu Pronunciation Lexicon Generator](https://mlsanity.com/paper/1801.00409/) (2018)

## Built on by (most cited first, 2 of 2)

- [WER We Stand: Benchmarking Urdu ASR Models](https://mlsanity.com/paper/2409.11252/) (2024)
- [Assessing the Feasibility of Lightweight Whisper Models for Low-Resource Urdu Transcription](https://mlsanity.com/paper/2508.09865/) (2025)

## Abstract (arXiv)

Call Centers have huge amount of audio data which can be used for achieving valuable business insights and transcription of phone calls is manually tedious task. An effective Automated Speech Recognition system can accurately transcribe these calls for easy search through call history for specific context and content allowing automatic call monitoring, improving QoS through keyword search and sentiment analysis. ASR for Call Center requires more robustness as telephonic environment are generally noisy. Moreover, there are many low-resourced languages that are on verge of extinction which can be preserved with help of Automatic Speech Recognition Technology. Urdu is the 10th most widely spoken language in the world, with 231,295,440 worldwide still remains a resource constrained language in ASR. Regional call-center conversations operate in local language, with a mix of English numbers and technical terms generally causing a "code-switching" problem. Hence, this paper describes an implementation framework of a resource efficient Automatic Speech Recognition/ Speech to Text System in a noisy call-center environment using Chain Hybrid HMM and CNN-TDNN for Code-Switched Urdu Language. Using Hybrid HMM-DNN approach allowed us to utilize the advantages of Neural Network with less labelled data. Adding CNN with TDNN has shown to work better in noisy environment due to CNN's additional frequency dimension which captures extra information from noisy speech, thus improving accuracy. We collected data from various open sources and labelled some of the unlabelled data after analysing its general context and content from Urdu language as well as from commonly used words from other languages, primarily English and were able to achieve WER of 5.2% with noisy as well as clean environment in isolated words or numbers as well as in continuous spontaneous speech.