ElizabethMwangi/whisper-large-v3-swahili-nss-afrivoice-cv

Whisper Large V3 — Swahili NSS (AfriVoice 5 Domains + Common Voice)

Stage 2 nonstandard speech fine-tune of openai/whisper-large-v3 on the CDLI Kenyan Swahili Nonstandard Speech dataset. Built on top of ElizabethMwangi/whisper-large-v3-swahili-afrivoice-cv, a Stage 1 checkpoint trained on AfriVoice (all 5 domains) interleaved with Common Voice Swahili.

Training Details

• Stage 1 base: ElizabethMwangi/whisper-large-v3-swahili-afrivoice-cv (AfriVoice 5 domains + Common Voice)
• Stage 2 dataset: cdli/kenyan_swahili_nonstandard_speech_v1.0 (849 examples)
• Language token: sw
• Full model training: encoder, decoder, and projection updated
• SpecAugment: On
• Learning rate: 5e-5 (polynomial decay, warmup 40 steps)
• Max steps: 1000
• Best checkpoint: step 550
• Output dir: sw_nss_tune_whisper_v3_large_afrivoice_v1.2

Results on Kenyan Swahili Nonstandard Speech (test set, best checkpoint)

Overall, compared to unadapted baseline

Model	Overall WER	Avg WER
openai/whisper-large-v3 (no adaptation)	0.845	-
Stage 1 only (afrivoice-cv, no NSS tuning)	0.498	-
This model (adapted)	0.328	0.276

Metric	Value
Overall WER	0.328
Overall CER	0.158
Avg WER	0.276
Avg CER	0.124
Meaning preservation	76.7%

By severity

Severity	WER	CER
Mild	0.21	0.09
Moderate	0.25	0.11
Severe	0.34	0.15