Custom vocabulary and technical acronyms

updated

Every engineering team and professional firm relies on unique terminology: internal project codenames, technical jargon, medical nomenclature, and foreign surnames. Out of the box, generic speech models can mishear these phrases. Oyma allows you to supply custom vocabulary prompts to steer Whisper’s decoder.

How initial prompt biasing works

OpenAI’s Whisper architecture accepts an initial text prompt that establishes linguistic context for speech decoding. When you register custom terms in Oyma, the speech engine feeds these phrases into the decoder prior to processing the first audio frame:

[Custom Terms: "ScreenCaptureKit, FTS5, Ollama, CommonMark, Wikilinks"]
                               │
                               ▼
┌─────────────────────────────────────────────────────────────┐
│                 Whisper Decoder Attention                   │
│   (Biased to recognize specialized terminology accurately)   │
└─────────────────────────────────────────────────────────────┘

Adding custom vocabulary

  1. Open Settings › Transcription › Vocabulary.
  2. Enter terms as a comma-separated list or newline-separated entries:
    ScreenCaptureKit, FTS5, Ollama, SQLite, CommonMark, APFS,
    Kubernetes, Datadog, Prometheus, GraphQL, WebRTC
  3. Click Save Vocabulary.

Best practices for vocabulary tuning

  • Capitalization Matters: Write acronyms in uppercase (OAuth, SLA, CI/CD) so Whisper outputs standard casing.
  • Compound Technical Terms: Separate multi-word phrases with standard spacing (PostgreSQL, Tailwind CSS).
  • Phonetic Hints for Foreign Names: If a colleague’s surname is frequently misspelled, include it in your vocabulary roster alongside common phonetics.

Questions

Can I teach Whisper new company codenames?

Yes. Add specialized terms to Settings › Transcription › Custom Vocabulary to bias speech decoding toward your terminology.

How does Whisper vocabulary biasing work?

Custom terms are passed as initial prompt context to Whisper's decoder, increasing the probability of matching phonetic sequences to your terms.

Is there a limit on custom vocabulary size?

We recommend keeping custom vocabulary under 100 terms to prevent decoder context degradation.

Your notes, in plain Markdown.

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