Posted on May 19, 2020 • Updated on Sep 25, 2021

Text To Speech In 3 Lines Of JavaScript

#javascript #webdev #api #codenewbie

If you're curious about trying this out, that's the 3 lines of code below 👇

var msg = new SpeechSynthesisUtterance();
msg.text = "Hello World";
window.speechSynthesis.speak(msg);

But if you're not in a hurry, this article explains everything you need to know about converting text to speech (spoken words) on the web with JavaScript.

Introduction

In a previous article, we'd explored the Web Speech API and also how to convert Speech To Text
Another amazing feature of the Web Speech API is to convert Text to Speech.

Note: Text To Speech != Speech To Text 🧐

Text To Speech is when we give the computer some words and the computer will say this words out loud in some robotic/human voice. While
Speech To Text is when we say some words to the computer, and what we'd just said will be converted to text (I guess this is explanatory enough)

Getting Started

The first thing we'll need to do is check if our browser supports the speech synthesis API. And the code below does that:

if ('speechSynthesis' in window) {
 // Speech Synthesis supported 🎉
}else{
  // Speech Synthesis Not Supported 😣
  alert("Sorry, your browser doesn't support text to speech!");
}

Next step is to create a new speechSynthesis object, add required property and make our app talk 👇

var msg = new SpeechSynthesisUtterance();
msg.text = "Good Morning";
window.speechSynthesis.speak(msg);

Code Explanation

Line 1: We created a variable msg, and the value assigned to it is a new instance of the speechSynthesis class.
Line 2: The .text property is used to specify the text we want to convert to speech
And finally, the code on the 3rd(last) line is what actually make our browser talks.

Altering Default Output

The speechSynthesis API gives room to also change alter the default output like changing the voice, volume, speech rate, language, pitch and more:

var msg = new SpeechSynthesisUtterance();
var voices = window.speechSynthesis.getVoices();
msg.voice = voices[10]; 
msg.volume = 1; // From 0 to 1
msg.rate = 1; // From 0.1 to 10
msg.pitch = 2; // From 0 to 2
msg.text = "Como estas Joel";
msg.lang = 'es';
speechSynthesis.speak(msg);

Getting Supported Voices

The code below helps you retrieve the list of all supported voices:

speechSynthesis.getVoices().forEach(function(voice) {
  console.log(voice.name, voice.default ? voice.default :'');
});

Conclusion

Well, there's nothing to conclude here I guess 🙃
But you could follow me on Twitter, I tweet and retweet interesting technical stuffs; you sure want to see em.

Thanks for reading 👏

Top comments (29)

Josias Aurel • May 20 '20

Unfortunately it didn't work for me

Asaolu Elijah 🧙‍♂️ • May 20 '20

Hi Josias,

Please note that the speechSynthesis API is not yet supported on all browsers.
The code below help you check for browser support:

if ('speechSynthesis' in window) {
 alert("Broswer supports speech synthesis 🎉");
}else{
  alert("Sorry, your browser doesn't support the speech synthesis API !");
}

Josias Aurel • May 20 '20

I use Chrome and it's says my browser supports it

lazarusWist • Dec 15 '20 • Edited

Check out MDN's speak easy synthesis demo which works on Chrome. There's two things you need to do to set it up properly:

1) As is the case with the Web Audio API generally, Chromium Browsers will not allow audio to be played without the user interacting with the page first. You need to put the speech synthesis code behind an event listener for some page event like a button click.

2) It seems that Chrome, unlike FireFox, does not have access to system voices when speechSynthesis is initialised for the first time. You need to add an event listener which refers to a function when the voices are found, something like - speechSynthesis.onvoiceschanged = getVoices. The technology is still experimental so I expect this will change in the future.

Richardengle • Feb 6 '21

codepen.io/richardengle/pen/KKNzKXg is my version of this, combined with some hacks. try it :]

Tiago Rangel • Dec 27 '22

Link down! No archive available

Jakub T. Jankiewicz • Jul 14 '22

This is old but see my comment. You need to wait for voices to load.

Felipe Matheus Ribeiro • May 29 '21

I am not getting make the code to work.

I am using firefox in linux OS
The browser can detect the SpeechSynthesisUtterance() but there is no voice or
any sound. I noticed that window.speechSynthesis.getVoices() don't return any voice.

Vukky • Nov 24 '22

You will need to have a text-to-speech dispatcher installed first, otherwise there's no TTS to use. See wiki.archlinux.org/title/List_of_a... for reference.

Boris Schapira • May 20 '20

Beware, the default voice locale is not the locale of the browser but the locale of the system. Be sure to always define the msg.lang (and the OS will switch to the right voice by itself).