The Speech Synthesis API: an introduction

The Speech Synthesis API: an introduction
by Janeth Kent Date: 05-02-2014 javascript programming webdev api

Today we’re going to focus on the Speech Synthesis API, which uses system libraries to speak, making the Web considerably more accessible.

NOTE: We have to consider that the API is fairly new, so not widely supported. The Speech Synthesis API is supported in Chrome 33+ and Safari. At the time of writing, the stable channel of Chrome is at version 32 so you will need to be running either the Chrome Dev channel or Chrome Canary to see this in action.

The simplest way to use this API is to pass a string to the SpeechSynthesisUtterance object and then use the speak method to have the computer say the string:

var message = new SpeechSynthesisUtterance(‘Hello World!’);  


Now, let's dig a little deeper to see how we can pass the attributes to modify the SpeechSynthesisUtterance object:

  • Text: this is the simplest, and the one we’ve already used.
  • Lang: this attribute will specify the language the synthesis should use (if nothing is specified it falls back on the document default).
  • VoiceURI: specifies the voice and the synthesis service you want to use.
  • Volume: the volume of the speech, from 0 to 1.
  • Rate: the speed at which the voice will speak. Values of 0 to 10 are permissable, but 1 is normal, 2 is double speed, 3 is triple speed and so on, so that 10 would be far too fast.
  • Pitch: the pitch of the voice ranging from 0 to 2.

To demonstrate, we’ll set up a form to determine the text, rate, pitch and volume:

<input type=“text” id=“speech"/><label for=“volume”>Volume</label>  
<input type=“range" max="1" min="0" step="0.1" value="1" id="volume">  
<label for=“rate”>Rate</label><input type=“range" max="5" min="0" step="0.5" value="2.5" id="rate"> 
<label for=“pitch”>Pitch</label><input type="range" max="2" min="0" step="0.1" value="2" id="pitch">  
<button id="talk">Speak</button>

So the first thing we need to do when it comes to the jQuery is to attach a click event to our talk button and then create a new instance of the SpeechSynthesisUtterance:

$("#talk").click(function() {   
var msg = new SpeechSynthesisUtterance();  });

After this is done we need to get the available voices, select the one we want to use and also set the voiceURI:

var voices = window.speechSynthesis.getVoices(); 
msg.voice = voices[10];   msg.voiceURI = 'native';

After this is done we need to move on to the attributes that will rely on user input and for that we will need to get the values of each input in our page using the .val() jQuery method, starting with the volume :

msg.volume = $(‘#volume’).val();

The method is the same for all the other inputs we have:

  msg.rate = $('#rate').val();  
msg.pitch = $('#pitch').val();    
msg.text = $('#speech').val();

Now all we really need to do in order to wrap this little application up is to set the language attribute and in this case I will use plain US English and then use the speechSynthesis.speakmethod to have the computer say the text with the settings we passed:

msg.lang = 'en-US';  speechSynthesis.speak(msg);

And that’s about all we needed to create a simple application using the Speech Synthesis API, this is the full code:

$("#talk").click(function() {    
var msg = new SpeechSynthesisUtterance();    
var voices = window.speechSynthesis.getVoices();   
 msg.voice = voices[10];     
msg.voiceURI = 'native';  
msg.volume = $('#volume').val();  
 msg.rate = $('#rate').val();   
 msg.pitch = $('#pitch').val();    
msg.text = $('#speech').val();    
msg.lang = 'en-US';    
speechSynthesis.speak(msg);  });


And you can also see a demo here.



Original post by Sara Vieira

by Janeth Kent Date: 05-02-2014 javascript programming webdev api hits : 13948  
Janeth Kent

Janeth Kent

Licenciada en Bellas Artes y programadora por pasión. Cuando tengo un rato retoco fotos, edito vídeos y diseño cosas. El resto del tiempo escribo en MA-NO WEB DESIGN AND DEVELOPMENT.


Related Posts

How to upload files to the server using JavaScript

In this tutorial we are going to see how you can upload files to a server using Node.js using JavaScript, which is very common. For example, you might want to…

How to combine multiple objects in JavaScript

In JavaScript you can merge multiple objects in a variety of ways. The most commonly used methods are the spread operator ... and the Object.assign() function.   How to copy objects with…

The Payment Request API: Revolutionizing Online Payments (Part 2)

In the first part of this series, we explored the fundamentals of the Payment Request API and how it simplifies the payment experience. Now, let's delve deeper into advanced features…

The Payment Request API: Revolutionizing Online Payments (Part 1)

The Payment Request API has emerged as the new standard for online payments, transforming the way transactions are conducted on the internet. In this two-part series, we will delve into…

Let's create a Color Picker from scratch with HTML5 Canvas, Javascript and CSS3

HTML5 Canvas is a technology that allows developers to generate real-time graphics and animations using JavaScript. It provides a blank canvas on which graphical elements, such as lines, shapes, images…

How do you stop JavaScript execution for a while: sleep()

A sleep()function is a function that allows you to stop the execution of code for a certain amount of time. Using a function similar to this can be interesting for…

Mastering array sorting in JavaScript: a guide to the sort() function

In this article, I will explain the usage and potential of the sort() function in JavaScript.   What does the sort() function do?   The sort() function allows you to sort the elements of…

Infinite scrolling with native JavaScript using the Fetch API

I have long wanted to talk about how infinite scroll functionality can be implemented in a list of items that might be on any Web page. Infinite scroll is a technique…

Sorting elements with SortableJS and storing them in localStorage

SortableJS is a JavaScript extension that you will be able to use in your developments to offer your users the possibility to drag and drop elements in order to change…

What is a JWT token and how does it work?

JWT tokens are a standard used to create application access tokens, enabling user authentication in web applications. Specifically, it follows the RFC 7519 standard. What is a JWT token A JWT token…

Template Literals in JavaScript

Template literals, also known as template literals, appeared in JavaScript in its ES6 version, providing a new method of declaring strings using inverted quotes, offering several new and improved possibilities. About…

How to use the endsWith method in JavaScript

In this short tutorial, we are going to see what the endsWith method, introduced in JavaScript ES6, is and how it is used with strings in JavaScript. The endsWith method is…