Web/API/SpeechRecognition/lang

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The lang property of the SpeechRecognition interface returns and sets the language of the current SpeechRecognition. If not specified, this defaults to the HTML lang attribute value, or the user agent's language setting if that isn't set either.

Syntax

var myLang = mySpeechRecognition.lang;
mySpeechRecognition.lang = 'en-US';

Value

A DOMString representing the BCP 47 language tag for the current SpeechRecognition.

Examples

This code is excerpted from our Speech color changer example.

var grammar = '#JSGF V1.0; grammar colors; public <color> = aqua | azure | beige | bisque | black | blue | brown | chocolate | coral | crimson | cyan | fuchsia | ghostwhite | gold | goldenrod | gray | green | indigo | ivory | khaki | lavender | lime | linen | magenta | maroon | moccasin | navy | olive | orange | orchid | peru | pink | plum | purple | red | salmon | sienna | silver | snow | tan | teal | thistle | tomato | turquoise | violet | white | yellow ;'
var recognition = new SpeechRecognition();
var speechRecognitionList = new SpeechGrammarList();
speechRecognitionList.addFromString(grammar, 1);
recognition.grammars = speechRecognitionList;
//recognition.continuous = false;
recognition.lang = 'en-US';
recognition.interimResults = false;
recognition.maxAlternatives = 1;

...

Specifications

Specification	Status	Comment
Web Speech APIThe definition of 'lang' in that specification.	Draft

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`lang` Experimental'	Chrome Full support 33 Prefixed' Notes' Full support 33 Prefixed' Notes' Prefixed' Implemented with the vendor prefix: webkit Notes' You'll need to serve your code through a web server for recognition to work.	Edge Full support ≤79 Prefixed' Notes' Full support ≤79 Prefixed' Notes' Prefixed' Implemented with the vendor prefix: webkit Notes' You'll need to serve your code through a web server for recognition to work.	Firefox No support No	IE No support No	Opera No support No	Safari No support No	WebView Android Full support Yes Prefixed' Notes' Full support Yes Prefixed' Notes' Prefixed' Implemented with the vendor prefix: webkit Notes' You'll need to serve your code through a web server for recognition to work.	Chrome Android Full support Yes Prefixed' Notes' Full support Yes Prefixed' Notes' Prefixed' Implemented with the vendor prefix: webkit Notes' You'll need to serve your code through a web server for recognition to work.	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android Full support Yes Prefixed' Notes' Full support Yes Prefixed' Notes' Prefixed' Implemented with the vendor prefix: webkit Notes' You'll need to serve your code through a web server for recognition to work.

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
See implementation notes.': See implementation notes.
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.

Firefox OS permissions

To use speech recognition in an app, you need to specify the following permissions in your manifest:

"permissions": {
  "audio-capture" : {
    "description" : "Audio capture"
  },
  "speech-recognition" : {
    "description" : "Speech recognition"
  }
}

You also need a privileged app, so you need to include this as well:

  "type": "privileged"