SpeechSynthesisUtterance.pitch

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The pitch property of the SpeechSynthesisUtterance interface gets and sets the pitch at which the utterance will be spoken at.

If unset, a default value of 1 will be used.

Syntax

// default 1
speechSynthesisUtteranceInstance.pitch = 1.5;

Value

A float representing the pitch value. It can range between 0 (lowest) and 2 (highest), with 1 being the default pitch for the current platform or voice. Some speech synthesis engines or voices may constrain the minimum and maximum rates further. If SSML is used, this value will be overridden by prosody tags in the markup.

Examples

var synth = window.speechSynthesis;

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

var voices = synth.getVoices();

  ...

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];
    }
  }
  utterThis.pitch = 1.5;
  synth.speak(utterThis);
  inputTxt.blur();
}

Specifications

Specification Status Comment
Web Speech API
The definition of 'pitch' in that specification.
Draft

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
pitch
Experimental
Chrome Full support 33Edge Full support 14Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0

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.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also