SpeechRecognitionPhrase

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The SpeechRecognitionPhrase interface of the Web Speech API represents a phrase that can be passed to the speech recognition engine for contextual biasing.

Instance properties

SpeechRecognitionPhrase.boost Read only

A floating point number representing the amount of boost you want to apply to the corresponding phrase.

SpeechRecognitionPhrase.phrase Read only

A string containing the word or phrase you want boosted in the recognition engine's bias.

Examples

Basic usage

The following code first creates an array containing the phrases to boost and their boost values. We convert this data into an ObservableArray of SpeechRecognitionPhrase objects by mapping the original array elements to SpeechRecognitionPhrase() constructor calls:

js
const phraseData = [
  { phrase: "azure", boost: 5.0 },
  { phrase: "khaki", boost: 3.0 },
  { phrase: "tan", boost: 2.0 },
];

const phraseObjects = phraseData.map(
  (p) => new SpeechRecognitionPhrase(p.phrase, p.boost),
);

After creating a SpeechRecognition instance, we add our contextual biasing phrases by setting the phraseObjects array as the value of the SpeechRecognition.phrases property:

js
const recognition = new SpeechRecognition();
recognition.continuous = false;
recognition.lang = "en-US";
recognition.interimResults = false;
recognition.processLocally = true;
recognition.phrases = phraseObjects;

// …

This code is excerpted from our on-device speech color changer (run the demo live). See Using the Web Speech API for a full explanation.

Specifications

Specification
Web Speech API
# speechrecognitionphrase

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
SpeechRecognitionPhrase
Experimental
Chrome – Full support
Chrome 142 (Release date: 2025-10-28)
footnote Full support
Edge – Full support
Edge 142 (Release date: 2025-10-31)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 126 (Release date: 2026-01-08)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support
SpeechRecognitionPhrase() constructor
Experimental
Chrome – Full support
Chrome 142 (Release date: 2025-10-28)
footnote Full support
Edge – Full support
Edge 142 (Release date: 2025-10-31)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 126 (Release date: 2026-01-08)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support
boost
Experimental
Chrome – Full support
Chrome 142 (Release date: 2025-10-28)
footnote Full support
Edge – Full support
Edge 142 (Release date: 2025-10-31)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 126 (Release date: 2026-01-08)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support
phrase
Experimental
Chrome – Full support
Chrome 142 (Release date: 2025-10-28)
footnote Full support
Edge – Full support
Edge 142 (Release date: 2025-10-31)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 126 (Release date: 2026-01-08)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.

See also