speech-paragraph

speech-paragraph

A Custom Element that extends the native paragraph HTML element <p> to enable it to read its text out loud using Web SpeechSynthesis.

Usage:

<script type="module" src="/src/speech-paragraph.js"></script>

<p is="speech-paragraph">
  This text will be read out loud.
</p>

In browsers that don't support extending native HTML elements, the element speech-paragraph can be used:

<script type="module" src="/src/speech-paragraph.js"></script>

<speech-paragraph>
  This text will be read out loud.
</speech-paragraph>

A play button will appear in the top-right corner of the paragraph. When pressed, the text of the paragraph will be read out loud and the play button will change into a pause button.

To cancel speaking instead of pausing, click outside the paragraph.

You can also select a portion of text inside the paragraph to play. In that case, the play button will appear at the start of the selection.

Selecting a language

The default language is US English, but you can specify the language with the lang attribute which takes as value a BCP 47 language tag.

For example: en-US or simply en.

<p is="speech-paragraph" lang="en-US">

<speech-paragraph lang="en-US">

Selecting a voice

For every language, the browser provides an array of available voices. A voice from this array can by chosen by specifying its name in the voice attribute.

To get the array of available voices, get a reference to the element and inspect the voices property. The easiest way to do this is to click the element in the Elements panel of your browser's dev tools which will assign it to the special $0 variable:

$0.voices

which will show the array of available voices like this:

0: SpeechSynthesisVoice {voiceURI: 'Alex', name: 'Alex', lang: 'en-US', localService: true, default: true}
1: SpeechSynthesisVoice {voiceURI: 'Fred', name: 'Fred', lang: 'en-US', localService: true, default: false}
2: SpeechSynthesisVoice {voiceURI: 'Samantha', name: 'Samantha', lang: 'en-US', localService: true, default: false}
3: SpeechSynthesisVoice {voiceURI: 'Victoria', name: 'Victoria', lang: 'en-US', localService: true, default: false}
4: SpeechSynthesisVoice {voiceURI: 'Google US English', name: 'Google US English', lang: 'en-US', localService: false, default: false}

A voice is selected by specifying its name property, so to select "Victoria":

<p is="speech-paragraph" lang="en-US" voice="Victoria">

<speech-paragraph lang="en-US" voice="Victoria">

Setting the playback speed

The speech at which the text is spoken can be set with the rate attribute. It accepts a value between 0.5 and 1.5. The default value is 1.

<p is="speech-paragraph" rate="0.8>

<speech-paragraph rate="0.8>

Styling

The component exposes the following CSS custom properties for styling :

• --button-size: size of the play and pause button. Default: 12px
• --button-color: color of the play and pause button. Default: #000000
• --text-highlight-color: background color of selected text inside the element. Default: #ffff00

Demo

To run the demo, run npm install once and then npm start and view the demo at http://localhost:8080