SpeechSynthesisUtterance

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage 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 specification 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 49 (49) No support ? 7
Feature Android Chrome Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support (Yes) (Yes) No support 2.0 No support No support 7.1

See also

Document Tags and Contributors

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