Custom vocabulary for dictation
Speech engines are trained on general language. They struggle with proper nouns, brand names, acronyms, and technical jargon. Mumbli lets you fix that.The problem
Without custom vocabulary, speech engines make predictable mistakes:| You say | You get | You wanted |
|---|---|---|
| ”VitePress" | "wheat press” | VitePress |
| ”ElevenLabs" | "11 labs” | ElevenLabs |
| ”Supabase" | "super base” | Supabase |
| ”kubectl" | "cube control” | kubectl |
The fix
Open Settings > Custom Vocabulary and add the words that matter to you. Mumbli uses them at two levels:Transcription hints
Your vocabulary is sent as a prompt hint to the speech-to-text engine (Groq Whisper). This biases the transcription toward your preferred spellings before any text is generated.
Benchmarked results
We tested 11 real vocabulary instances that were consistently mistranscribed:| Metric | Without vocabulary | With vocabulary |
|---|---|---|
| Exact match accuracy | 36% | 100% |
| Test instances | 11 | 11 |
What to add
Good candidates for your vocabulary list:- People’s names — colleagues, contacts, public figures
- Brand names — products, companies, services you mention often
- Technical terms — frameworks, libraries, CLI tools, protocols
- Acronyms — spelled out the way you want them (e.g., “GROQ” not “grock”)
- Domain-specific jargon — medical terms, legal terms, industry language
Engine support
| Engine | STT hints | Polish corrections |
|---|---|---|
| Standard (ElevenLabs) | Not supported (Scribe v1) | Yes |
| Fast (Groq Whisper) | Yes | Yes |
Download Mumbli
Free and open source. Add your vocabulary in Settings after install.