Results
Word error rate (%), greedy decoding, one normalizer for every system (bangla_asr.common.text.normalize_bangla_text).
In brackets: the spelling-aware WER, which does not count differences that human annotators confirmed as spelling only
(ছিল / ছিলো).
Table with columns: Test set, This model, Zero-shot base model| Test set | This model | Zero-shot base model |
|---|
| DL Sprint 4.0 eval (media speech, 4,234 clips) | 11.18 (8.82) | 22.70 (15.82) |
| FLEURS test | 15.60 (10.89) | 21.54 (14.56) |
| Common Voice test | 10.13 (6.61) | 14.80 (10.15) |
| Kathbath validation | 10.28 (5.87) | 14.81 (9.02) |
| Average | 11.80 (8.04) | 18.46 (12.39) |
Against the open Bangla models scored with the same harness it is best on DL Sprint, Common Voice and Kathbath among
the models not trained on those sets; on FLEURS the non-commercial Hishab conformer is ahead (14.24). Against 605
human-verified references the order of the systems is unchanged.
Whole raw recordings (22, 20.4 h, cut by voice detection): 14.2% WER. Speed: real-time factor about 0.04 on a T4.
Use
from transformers import pipeline asr = pipeline("automatic-speech-recognition", model="OmiKhan/bangla-asr-whisper-medium")print(asr("clip.wav", generate_kwargs={"language": "bn", "task": "transcribe"})["text"])
Audio is resampled to 16 kHz. The model was trained and scored on clips of 1–25 s; for long recordings, cut the audio
at pauses (for example with Silero VAD) or pass chunk_length_s=30.
Training
Full fine-tuning, 2 epochs, learning rate 1e-5, from the tugstugi Whisper-medium checkpoint. The released weights are
a weight average of two runs with the same recipe, chosen by a rule fixed before any test score (lowest average WER
over three development sets): 0.25 × M1 (DL Sprint, 60 h) + 0.75 × M5-300 (all data below, ~300 h).
Table with columns: Data, Hours used, License| Data | Hours used | License |
|---|
| DL Sprint 4.0 long-form ASR (Bengali-Loop), training recordings, forced-aligned | ~60 | no license stated; see below |
| Common Voice 27.0, Bengali (train) | ~34 | CC0 |
| Kathbath, Bengali (train) | ~34 | CC BY 4.0 |
| Shrutilipi, Bengali | ~28 | CC BY 4.0 |
| OpenSLR 53, Large Bengali ASR training data | ~144 | CC BY-SA 4.0 |
The test sets are the corpora's official test (or validation) splits; OpenSLR 53 sentences that also occur in a test
set were removed before training.
Limitations
- Scored on forced-aligned clips; whole recordings are harder (14.2% WER above).
- Spelling follows the training corpora's conventions, which differ between corpora (15–50% of the remaining errors
are spelling only).
- Regional dialects are written as the transcripts of the training data write them; strongly dialectal speech is less
well covered.
Data provenance and takedown
The DL Sprint 4.0 audio comes from public Bangla YouTube channels and is subject to the competition's rules, which
state no data license; no audio is included in this repository. If you are a rights holder or the organizers and want
a model or derived material removed, open an issue at github.com/omikhan4901/asr.
Citation
Mehboob Ehsan Khan, Nabigah Bin Sayeed, Nafisa Rodela. Why N-best Rescoring Plateaus for Bangla Speech Recognition,
and How Far Fixing the Cause Goes. CSE499 capstone, North South University, 2026. github.com/omikhan4901/asr