The speechSynthesis read-only property of the Window object returns a SpeechSynthesis object, which is the entry point into using Web Speech API speech synthesis functionality.
The speechSynthesis read-only property of the Window object returns a SpeechSynthesis object, which is the entry point into using Web Speech API speech synthesis functionality.
A SpeechSynthesis object.
 In our basic Speech synthesizer 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(), create a new SpeechSynthesisUtterance 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.
js
const synth = window.speechSynthesis; const inputForm = document.querySelector("form"); const inputTxt = document.querySelector("input"); const voiceSelect = document.querySelector("select"); function populateVoiceList() { voices = synth.getVoices(); for (const voice of voices) { const option = document.createElement("option"); option.textContent = `${voice.name} (${voice.lang})`; if (voice.default) { option.textContent += " — DEFAULT"; } option.setAttribute("data-lang", voice.lang); option.setAttribute("data-name", voice.name); voiceSelect.appendChild(option); } } populateVoiceList(); if (speechSynthesis.onvoiceschanged !== undefined) { speechSynthesis.onvoiceschanged = populateVoiceList; } inputForm.onsubmit = (event) => { event.preventDefault(); const utterThis = new SpeechSynthesisUtterance(inputTxt.value); const selectedOption = voiceSelect.selectedOptions[0].getAttribute("data-name"); utterThis.voice = voices.find((v) => v.name === selectedOption); synth.speak(utterThis); inputTxt.blur(); };
| Specification | 
|---|
| Web Speech API  # tts-section  | 
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
speechSynthesis | 
33 | 14 | 49 | No | 20 | 7 | No | 33 | 49 | No | 7 | 2.0 | 
    © 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
    https://developer.mozilla.org/en-US/docs/Web/API/Window/speechSynthesis