VoiceFragment.kt

    private var speechRecognizer: SpeechRecognizer? = null

    ...

    private fun listenToSpeechInput() {
        speechRecognizer = SpeechRecognizer.createSpeechRecognizer(context)
        speechRecognizer?.setRecognitionListener(object: RecognitionListener {
            ...
            override fun onResults(p0: Bundle?) {
                speechRecognizer?.stopListening()
                requestExtractQuery(p0, true)
            }
        })
    }