SpeechRecognitionPhrase: SpeechRecognitionPhrase() constructor

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

The SpeechRecognitionPhrase() constructor creates a new SpeechRecognitionPhrase object.

An array of SpeechRecognitionPhrase objects is passed into the speech recognition engine via the SpeechRecognition.phrases property for contextual biasing.

Syntax

new SpeechRecognitionPhrase(phrase)
new SpeechRecognitionPhrase(phrase, boost)

phrase: A string containing a word or phrase you want boosted.
boost Optional: A floating point number between 0.0 and 10.0 (inclusive) that represents the weight you want to apply to the phrase. This value is roughly equivalent to the natural log of the number of times more likely the website thinks this phrase to appear than what the speech recognition model knows. Higher values make the phrase more likely to be recognized. A value of 0.0 means the phrase is not boosted at all, whereas a value of 10.0 means the phrase is extremely likely to appear. If not specified, the boost defaults to 1.0.

Note: A high value such as 9.0 or 10.0 might make the recognition engine erroneously recognize other phrases as the specified phrase. Therefore, such values should be used rarely when constructing SpeechRecognitionPhrase objects.

SyntaxError DOMException: The specified boost value is less than 0.0 or greater than 10.0.

Specification
Web Speech API # dom-speechrecognitionphrase-speechrecognitionphrase

	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()` 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

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