SpeechSynthesisUtterance: volume property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨September 2018⁩.

The volume property of the SpeechSynthesisUtterance interface gets and sets the volume that the utterance will be spoken at.

If not set, the default value 1 will be used.

Value

A float that represents the volume value, between 0 (lowest) and 1 (highest.)

If SSML is used, this value will be overridden by prosody tags in the markup.

Examples

const synth = window.speechSynthesis;
const inputForm = document.querySelector("form");
const inputTxt = document.querySelector("input");
const voiceSelect = document.querySelector("select");
const voices = synth.getVoices();
// ...
inputForm.onsubmit = (event) => {
 event.preventDefault();
 const utterThis = new SpeechSynthesisUtterance(inputTxt.value);
 const selectedOption =
 voiceSelect.selectedOptions[0].getAttribute("data-name");
 for (const voice of voices) {
 if (voice.name === selectedOption) {
 utterThis.voice = voice;
 }
 }
 utterThis.volume = 0.5;
 synth.speak(utterThis);
 inputTxt.blur();
};