Bias Phrase Lab

Run two SpeechRecognition instances simultaneously — one with contextual biasing phrases in a SpeechGrammarList, one without — and compare how domain-specific vocabulary fares in each transcript.

Bias phrase list

Add domain-specific words. These will be injected into a SpeechGrammarList for the "With bias" recogniser.

Presets:
Ready
Without bias
Transcript will appear here…
Accuracy
—
With bias
Transcript will appear here…
Accuracy
—

How it works

The SpeechGrammarList API (part of Chrome's contextual biasing in v142) lets you hint the speech engine toward specific vocabulary. A JSGF grammar string lists the bias phrases with a weight; the engine boosts their prior probability during decoding.

const grammar = '#JSGF V1.0; grammar bias; public <bias> = ' +
  phrases.join(' | ') + ' ;';
const list = new webkitSpeechGrammarList();
list.addFromString(grammar, 1);
recognition.grammars = list;