Speech

expo-speech provides an API that allows you to utilize Text-to-speech functionality in your app.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web

Installation

expo install expo-speech

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Usage

import * as React from 'react';
import { View, StyleSheet, Button } from 'react-native';
import * as Speech from 'expo-speech';

export default function App() {
  const speak = () => {
    const thingToSay = '1';
    Speech.speak(thingToSay);
  };

  return (
    <View style={styles.container}>
      <Button title="Press to hear some words" onPress={speak} />
    </View>
  );
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: '#ecf0f1',
    padding: 8,
  },
});

API

import * as Speech from 'expo-speech';

Constants

`Speech.maxSpeechInputLength`

Maximum possible text length acceptable by Speech.speak() method. It is platform-dependent. On iOS, this returns Number.MAX_VALUE.

Methods

`Speech.speak(text, options)`

Speak out loud the text given options. Calling this when another text is being spoken adds an utterance to queue.

Arguments

text (string) -- The text to be spoken. Cannot be longer than Speech.maxSpeechInputLength.
options (object) --
A map of options:
- voice (string) -- Voice identifier
- language (string) -- The code of a language that should be used to read the text, check out IETF BCP 47 to see valid codes.
- pitch (number) -- Pitch of the voice to speak text. 1.0 is the normal pitch.
- rate (number) -- Rate of the voice to speak text. 1.0 is the normal rate.
- onStart (function) -- A callback that is invoked when speaking starts.
- onDone (function) -- A callback that is invoked when speaking finishes.
- onStopped (function) -- A callback that is invoked when speaking is stopped by calling Speech.stop().
- onError (function) -- (Android only). A callback that is invoked when an error occurred while speaking.

Error Codes

ERR_SPEECH_INPUT_LENGTH

`Speech.stop()`

Interrupts current speech and deletes all in queue.

`Speech.pause()`

Pauses current speech.

`Speech.resume()`

Resumes speaking previously paused speech or does nothing if there's none.

`Speech.isSpeakingAsync()`

Determine whether the Text-to-speech utility is currently speaking. Will return true if speaker is paused.

Returns

Returns a Promise that resolves to a boolean, true if speaking, false if not.

`Speech.getAvailableVoicesAsync()`

Returns list of all available voices.

Returns

List of Voice objects.

`Voice`

Field	Type
identifier	string
name	string
quality	enum Speech.VoiceQuality
language	string

Enum Types

`Speech.VoiceQuality`

VoiceQuality.Default
VoiceQuality.Enhanced

Error Codes

`ERR_SPEECH_INPUT_LENGTH`

An error occurred when length of text parameter provided to Speech.speak() exceeds its limit. To see the limit, use Speech.maxSpeechInputLength.