DLRG@DravidianLangTech 2026: Dual-Purpose Whisper Adaptation for Tamil Dialect Identification and Dialectal Speech Recognition

Gulisetty Abhinav, Tanisha Nanda, Ramesh Kannan R, Ratnavel Rajalakshmi


Abstract
This paper describes our system developed for the shared task on Dialect Based Speech Recognition and Classification in Tamil at DravidianLangTech@ACL 2026. We participated in both Subtask 1 (Dialect Identification) and Subtask 2 (Dialectal ASR). Our approach leverages a single Tamil-adapted Whisper Medium model as a unified foundation for both tasks. For dialect classification, we have used the Whisper encoder as a feature extractor by discarding the decoder, applying mean pooling over the temporal dimension, and fine-tuning the full encoder with a lightweight classification head, achieving 73.4% accuracy on the test set. For dialectal ASR, we apply Low-Rank Adaptation (LoRA) to the full encoder-decoder architecture with SpecAugment-based data augmentation, achieving a Word Error Rate (WER) of 0.55 on the test set. Our experiments reveal that unfreezing the pre-trained encoder is critical for dialect discrimination, boosting accuracy from 52.78% (frozen) to 73.4% (unfrozen). The code is publicly available at https://github.com/DLRG-VIT/DravidianLangTech2026
Anthology ID:
2026.dravidianlangtech-1.33
Volume:
Proceedings of the Sixth Workshop on Speech, Vision, and Language Technologies for Dravidian Languages
Month:
July
Year:
2026
Address:
Underline (Virtual)
Editors:
Bharathi Raja Chakravarthi, Ruba Priyadharshini, Anand Kumar Madasamy, Sajeetha Thavareesan, Saranya Rajiakodi, Subalalitha Navaneethakrishnan, Dhivya Chinnappa, Balasubramanian Palani, Malliga Subramanian, Kogilavani Shanmugavadivel, Ratnavel Rajalakshmi
Venues:
DravidianLangTech | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
232–236
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.dravidianlangtech-1.33/
DOI:
Bibkey:
Cite (ACL):
Gulisetty Abhinav, Tanisha Nanda, Ramesh Kannan R, and Ratnavel Rajalakshmi. 2026. DLRG@DravidianLangTech 2026: Dual-Purpose Whisper Adaptation for Tamil Dialect Identification and Dialectal Speech Recognition. In Proceedings of the Sixth Workshop on Speech, Vision, and Language Technologies for Dravidian Languages, pages 232–236, Underline (Virtual). Association for Computational Linguistics.
Cite (Informal):
DLRG@DravidianLangTech 2026: Dual-Purpose Whisper Adaptation for Tamil Dialect Identification and Dialectal Speech Recognition (Abhinav et al., DravidianLangTech 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.dravidianlangtech-1.33.pdf