SpeechSynthesisUtterance

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.)

SpeechSynthesisUtterance.SpeechSynthesisUtterance() (en-US)

Returns a new SpeechSynthesisUtterance object instance.

SpeechSynthesisUtterance also inherits properties from its parent interface, EventTarget.

SpeechSynthesisUtterance.lang (en-US)

Gets and sets the language of the utterance.

SpeechSynthesisUtterance.pitch (en-US)

Gets and sets the pitch at which the utterance will be spoken at.

SpeechSynthesisUtterance.rate (en-US)

Gets and sets the speed at which the utterance will be spoken at.

SpeechSynthesisUtterance.text (en-US)

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 (en-US)

Gets and sets the volume that the utterance will be spoken at.

SpeechSynthesisUtterance.onboundary (en-US)

Fired when the spoken utterance reaches a word or sentence boundary.

SpeechSynthesisUtterance.onend (en-US)

Fired when the utterance has finished being spoken.

SpeechSynthesisUtterance.onerror (en-US)

Fired when an error occurs that prevents the utterance from being succesfully spoken.

SpeechSynthesisUtterance.onmark (en-US)

Fired when the spoken utterance reaches a named SSML "mark" tag.

SpeechSynthesisUtterance.onpause (en-US)

Fired when the utterance is paused part way through.

SpeechSynthesisUtterance.onresume (en-US)

Fired when a paused utterance is resumed.

SpeechSynthesisUtterance.onstart (en-US)

Fired when the utterance has begun to be spoken.

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() (en-US) 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 (en-US) 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() (en-US) 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();
}

• Web Speech API