SpeechSynthesisUtterance

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.

Listen to these events using addEventListener() or by assigning an event listener to the oneventname property of this interface.

boundary (en-US)

Fired when the spoken utterance reaches a word or sentence boundary. Also available via the onboundary (en-US) property.

end (en-US)

Fired when the utterance has finished being spoken. Also available via the onend (en-US) property.

error (en-US)

Fired when an error occurs that prevents the utterance from being succesfully spoken. Also available via the onerror (en-US) property

mark (en-US)

Fired when the spoken utterance reaches a named SSML "mark" tag. Also available via the onmark (en-US) property.

pause (en-US)

Fired when the utterance is paused part way through. Also available via the onpause (en-US) property.

resume (en-US)

Fired when a paused utterance is resumed. Also available via the onresume (en-US) property.

start (en-US)

Fired when the utterance has begun to be spoken. Also available via the onstart (en-US) property.

In our basic Speech synthesiser demo (source), 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 (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 voices = synth.getVoices();

var inputForm = document.querySelector('form');
var inputTxt = document.querySelector('input');
var voiceSelect = document.querySelector('select');

for(var i = 0; i < voices.length; i++) {
  var option = document.createElement('option');
  option.textContent = voices[i].name + ' (' + voices[i].lang + ')';
  option.value = i;
  voiceSelect.appendChild(option);
}

inputForm.onsubmit = function(event) {
  event.preventDefault();

  var utterThis = new SpeechSynthesisUtterance(inputTxt.value);
  utterThis.voice = voices[voiceSelect.value];
  synth.speak(utterThis);
  inputTxt.blur();
}

• Web Speech API