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.transcriptRead only- Returns a string containing the transcript of the recognised word.
SpeechRecognitionAlternative.confidenceRead 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
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
SpeechRecognitionAlternative | Chrome
Full support
33
| Edge
Full support
≤79
| Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android
Full support
Yes
| Chrome Android
Full support
Yes
| Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android
Full support
Yes
|
confidence | Chrome
Full support
33
| Edge
Full support
≤79
| Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android
Full support
Yes
| Chrome Android
Full support
Yes
| Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android
Full support
Yes
|
transcript | Chrome
Full support
33
| Edge
Full support
≤79
| Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android
Full support
Yes
| Chrome Android
Full support
Yes
| Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android
Full support
Yes
|
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.
