This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.
The SpeechSynthesisUtterance
interface of the Web Speech API represents a speech request. It contains the content the speech service should read and information about how to read it (e.g. language, pitch and volume.)
Constructor
SpeechSynthesisUtterance.SpeechSynthesisUtterance()
- Returns a new
SpeechSynthesisUtterance
object instance.
Properties
SpeechSynthesisUtterance
also inherits properties from its parent interface, EventTarget
.
SpeechSynthesisUtterance.lang
- Gets and sets the language of the utterance.
SpeechSynthesisUtterance.pitch
- Gets and sets the pitch at which the utterance will be spoken at.
SpeechSynthesisUtterance.rate
- Gets and sets the speed at which the utterance will be spoken at.
SpeechSynthesisUtterance.text
- Gets and sets the text that will be synthesised when the utterance is spoken.
SpeechSynthesisUtterance.voice
- Gets and sets the voice that will be used to speak the utterance.
SpeechSynthesisUtterance.volume
- Gets and sets the volume that the utterance will be spoken at.
Event handlers
SpeechSynthesisUtterance.onboundary
- Fired when the spoken utterance reaches a word or sentence boundary.
SpeechSynthesisUtterance.onend
- Fired when the utterance has finished being spoken.
SpeechSynthesisUtterance.onerror
- Fired when an error occurs that prevents the utterance from being succesfully spoken.
SpeechSynthesisUtterance.onmark
- Fired when the spoken utterance reaches a named SSML "mark" tag.
SpeechSynthesisUtterance.onpause
- Fired when the utterance is paused part way through.
SpeechSynthesisUtterance.onresume
- Fired when a paused utterance is resumed.
SpeechSynthesisUtterance.onstart
- Fired when the utterance has begun to be spoken.
Examples
In our basic Speech synthesiser demo, we first grab a reference to the SpeechSynthesis controller using window.speechSynthesis
. After defining some necessary variables, we retrieve a list of the voices available using SpeechSynthesis.getVoices()
and populate a select menu with them so the user can choose what voice they want.
Inside the inputForm.onsubmit
handler, we stop the form submitting with preventDefault(), use the constructor
to create a new utterance instance containing the text from the text <input>
, set the utterance's voice
to the voice selected in the <select>
element, and start the utterance speaking via the SpeechSynthesis.speak()
method.
var synth = window.speechSynthesis; var inputForm = document.querySelector('form'); var inputTxt = document.querySelector('input'); var voiceSelect = document.querySelector('select'); var voices = synth.getVoices(); for(i = 0; i < voices.length ; i++) { var option = document.createElement('option'); option.textContent = voices[i].name + ' (' + voices[i].lang + ')'; option.setAttribute('data-lang', voices[i].lang); option.setAttribute('data-name', voices[i].name); voiceSelect.appendChild(option); } inputForm.onsubmit = function(event) { event.preventDefault(); var utterThis = new SpeechSynthesisUtterance(inputTxt.value); var selectedOption = voiceSelect.selectedOptions[0].getAttribute('data-name'); for(i = 0; i < voices.length ; i++) { if(voices[i].name === selectedOption) { utterThis.voice = voices[i]; } } synth.speak(utterThis); inputTxt.blur(); }
Specifications
Specification | Status | Comment |
---|---|---|
Web Speech API The definition of 'SpeechSynthesisUtterance' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 33 | 44 (44) [1] | Not supported | Not supported | Not supported |
Feature | Android | Chrome | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | ? | 2.5 | Not supported | Not supported | Not supported |
- [1] Can be enabled via the
media.webspeech.synth.enabled
flag in about:config.