How to Implement Text-to-Speech in JavaScript

Why Your Web App Needs a Voice

Imagine this: you’re building an educational app for kids. You’ve got colorful visuals, interactive quizzes, and even gamified rewards. But something feels missing. Your app doesn’t “speak” to its users. Now, imagine adding a feature where the app reads out questions, instructions, or even congratulates the user for a job well done. Suddenly, your app feels alive, engaging, and accessible to a wider audience, including those with visual impairments or reading difficulties.

That’s the magic of text-to-speech (TTS). And the best part? You don’t need a third-party library or expensive tools. With JavaScript’s speechSynthesis API, you can implement TTS in just a few lines of code. But as with any technology, there are nuances, pitfalls, and best practices to consider. Let’s dive deep into how you can make your web app talk, the right way.

Understanding the speechSynthesis API

The speechSynthesis API is part of the Web Speech API, a native browser feature that enables text-to-speech functionality. It works by leveraging the speech synthesis engine available on the user’s device, meaning no additional downloads or installations are required. This makes it lightweight and fast to implement.

At its core, the API revolves around the SpeechSynthesisUtterance object, which represents the text you want to convert to speech. By configuring its properties—such as the text, voice, language, pitch, and rate—you can customize the speech output to suit your application’s needs.

Basic Example: Hello, World!

Here’s a simple example to get you started:

// Create a new SpeechSynthesisUtterance instance
const utterance = new SpeechSynthesisUtterance();

// Set the text to be spoken
utterance.text = "Hello, world!";

// Set the language of the utterance
utterance.lang = 'en-US';

// Play the utterance using the speech synthesis engine
speechSynthesis.speak(utterance);

Run this code in your browser’s console, and you’ll hear your computer say, “Hello, world!” It’s that simple. But simplicity often hides complexity. Let’s break it down and explore how to make this feature production-ready.
Customizing the Speech Output
The default settings are fine for a quick demo, but real-world applications demand more control. The SpeechSynthesisUtterance object provides several properties to customize the speech output:
1. Choosing a Voice
Different devices and browsers support various voices, and the speechSynthesis.getVoices() method retrieves a list of available options. Here’s how you can select a specific voice:
    

        

            

                📚 Continue Reading
            
            

                Sign in with your Google or Facebook account to read the full article.
                
It takes just 2 seconds!
            
            

                
Continue with Google
            
            

                Already have an account? Log in here