Beyond Monolingual Limits: Fine-Tuning Monolingual ASR for Yoruba-English Code-Switching

Oreoluwa Boluwatife Babatunde, Victor Tolulope Olufemi, Emmanuel Bolarinwa, Kausar Yetunde Moshood, Chris Chinenye Emezue


Abstract
Code-switching (CS) presents a significant challenge for Automatic Speech Recognition (ASR) systems, particularly in low-resource settings. While multilingual ASR models like OpenAI Whisper Large v3 are designed to handle multiple languages, their high computational demands make them less practical for real-world deployment in resource-constrained environments. In this study, we investigate the effectiveness of fine-tuning both monolingual and multilingual ASR models for Yoruba-English CS speech. Our results show that unadapted monolingual ASR models outperform Whisper Large v3 in a zero-shot setting on CS speech. Fine-tuning significantly reduces WER for both monolingual and multilingual models, with monolingual models achieving over a 20% WER reduction on CS and Yoruba speech while maintaining lower computational costs. However, we observe a trade-off, as fine-tuning leads to some degradation in English recognition, particularly for multilingual models. Our findings highlight that while multilingual models benefit from fine-tuning, monolingual models provide a computationally efficient and competitive alternative for CS-ASR, making them a viable choice for resource-constrained environments.
Anthology ID:
2025.calcs-1.3
Volume:
Proceedings of the 7th Workshop on Computational Approaches to Linguistic Code-Switching
Month:
May
Year:
2025
Address:
Albuquerque, New Mexico, USA
Editors:
Genta Indra Winata, Sudipta Kar, Marina Zhukova, Thamar Solorio, Xi Ai, Injy Hamed, Mahardika Krisna Krisna Ihsani, Derry Tanti Wijaya, Garry Kuwanto
Venues:
CALCS | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
18–25
Language:
URL:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.calcs-1.3/
DOI:
Bibkey:
Cite (ACL):
Oreoluwa Boluwatife Babatunde, Victor Tolulope Olufemi, Emmanuel Bolarinwa, Kausar Yetunde Moshood, and Chris Chinenye Emezue. 2025. Beyond Monolingual Limits: Fine-Tuning Monolingual ASR for Yoruba-English Code-Switching. In Proceedings of the 7th Workshop on Computational Approaches to Linguistic Code-Switching, pages 18–25, Albuquerque, New Mexico, USA. Association for Computational Linguistics.
Cite (Informal):
Beyond Monolingual Limits: Fine-Tuning Monolingual ASR for Yoruba-English Code-Switching (Babatunde et al., CALCS 2025)
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PDF:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.calcs-1.3.pdf