SpeechRecognition#

The SpeechRecognition interface provides a high-level API for performing speech recognition. It supports real-time speech recognition and recognition of audio files, offering flexibility in a variety of use cases.

#Features Overview

• Real-Time Recognition: Transcribe live audio from the microphone.
• File-Based Recognition: Analyze and transcribe recorded audio files.
• Multi-Language Support: Specify the recognition locale for different languages.
• Intermediate Results: Access partial and final results for progressive transcription.
• Custom Callbacks: Handle transcription results and sound level changes with event listeners.

#Type Definitions

#RecognitionTaskHint

Hints for the type of task for which speech recognition is used:

• 'confirmation': For commands like "yes," "no," or "maybe."
• 'dictation': For tasks similar to keyboard dictation.
• 'search': For identifying search terms.
• 'unspecified': For general-purpose speech recognition.

#SpeechRecognitionResult

Represents the result of speech recognition:

• isFinal: Indicates if the transcription is complete and final.
• text: The transcription as a user-displayable string, with the highest confidence level.

#Static Properties

#Supported Locales

• supportedLocales: Returns a list of locales supported by the speech recognizer, such as "en-US", "fr-FR", or "zh-CN".

#Recognition State

• isRecognizing: Indicates whether a recognition request is currently active.

#Methods

#Start Real-Time Recognition

start(options: object): Promise<boolean>
Starts speech recognition from the device microphone.

#Options

• locale: Locale string for the desired language (optional).
• partialResults: Return intermediate results (default: true).
• addsPunctuation: Automatically add punctuation to results (default: false).
• requestOnDeviceRecognition: Keep audio data on the device (default: false).
• taskHint: Specify the recognition task type ('confirmation', 'dictation', 'search', 'unspecified').
• useDefaultAudioSessionSettings: Use default audio session settings (default: true).
• onResult: Callback for recognition results (SpeechRecognitionResult).
• onSoundLevelChanged: Callback for sound level changes (optional).

#Example

await SpeechRecognition.start({
  locale: "en-US",
  partialResults: true,
  addsPunctuation: true,
  onResult: (result) => {
    console.log("Transcription:", result.text)
  },
  onSoundLevelChanged: (level) => {
    console.log("Sound Level:", level)
  }
})

#Recognize Speech in Audio Files

recognizeFile(options: object): Promise<boolean>
Starts recognition for a recorded audio file.

#Options

• filePath: Path to the audio file.
• locale: Locale string for the desired language (optional).
• partialResults: Return intermediate results (default: false).
• addsPunctuation: Automatically add punctuation to results (default: false).
• requestOnDeviceRecognition: Keep audio data on the device (default: false).
• taskHint: Specify the recognition task type ('confirmation', 'dictation', 'search', 'unspecified').
• onResult: Callback for recognition results (SpeechRecognitionResult).

#Example

await SpeechRecognition.recognizeFile({
  filePath: FileManager.join(FileManager.documentDirectory, "example.wav"),
  locale: "en-US",
  addsPunctuation: true,
  onResult: (result) => {
    console.log("File Transcription:", result.text)
  }
})

#Stop Recognition

stop(): Promise<void>
Stops an active speech recognition session.

#Example

await SpeechRecognition.stop()

#Examples

#Real-Time Recognition with Progress Updates

await SpeechRecognition.start({
  locale: "en-US",
  onResult: (result) => {
    console.log(result.isFinal ? "Final Result:" : "Partial Result:", result.text)
  },
  onSoundLevelChanged: (level) => {
    console.log("Sound Level:", level)
  }
})

#Recognize Audio File

await SpeechRecognition.recognizeFile({
  filePath: FileManager.join(FileManager.documentDirectory, "audio.m4a"),
  partialResults: false,
  onResult: (result) => {
    console.log("File recognition completed. Transcription:", result.text)
  }
})

#Stop Active Recognition

if (await SpeechRecognition.start({
  // ...
})) {
  // Stop after 10 seconds.
  setTimeout(() => {
    await SpeechRecognition.stop()
  }, 10 * 1000)
}

#Notes

• Ensure the necessary microphone or file access permissions are granted before using this API.
• Use supportedLocales to determine available languages for recognition.
• For optimal performance, use audio files in formats supported by iOS (e.g., .wav, .m4a).