SpeechRecognitionAlternative

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

The SpeechRecognitionAlternative interface of the Web Speech API represents a single word that has been recognised by the speech recognition service.

Properties

SpeechRecognitionAlternative.transcript Read only
Returns a string containing the transcript of the recognised word.
SpeechRecognitionAlternative.confidence Read only
Returns a numeric estimate of how confident the speech recognition system is that the recognition is correct.

Examples

This code is excerpted from our Speech color changer example.

recognition.onresult = function(event) {
  // The SpeechRecognitionEvent results property returns a SpeechRecognitionResultList object
  // The SpeechRecognitionResultList object contains SpeechRecognitionResult objects.
  // It has a getter so it can be accessed like an array
  // The first [0] returns the SpeechRecognitionResult at position 0.
  // Each SpeechRecognitionResult object contains SpeechRecognitionAlternative objects that contain individual results.
  // These also have getters so they can be accessed like arrays.
  // The second [0] returns the SpeechRecognitionAlternative at position 0.
  // We then return the transcript property of the SpeechRecognitionAlternative object
  var color = event.results[0][0].transcript;
  diagnostic.textContent = 'Result received: ' + color + '.';
  bg.style.backgroundColor = color;
}

Specifications

Specification Status Comment
Web Speech API
The definition of 'SpeechRecognitionAlternative' in that specification.
Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic support
Experimental
Chrome Full support 33
Prefixed Notes
Full support 33
Prefixed Notes
Prefixed Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge ? Firefox No support NoIE No support NoOpera No support NoSafari No support NoWebView Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Requires 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 Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge Mobile ? Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android ?
confidence
Experimental
Chrome Full support 33
Prefixed Notes
Full support 33
Prefixed Notes
Prefixed Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge ? Firefox No support NoIE No support NoOpera No support NoSafari No support NoWebView Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Requires 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 Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge Mobile ? Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android ?
transcript
Experimental
Chrome Full support 33
Prefixed Notes
Full support 33
Prefixed Notes
Prefixed Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge ? Firefox No support NoIE No support NoOpera No support NoSafari No support NoWebView Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Requires 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 Requires the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge Mobile ? Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
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"

See also

Document Tags and Contributors

Contributors to this page: lucian95, chrisdavidmills
Last updated by: lucian95,