MediaStreamTrack audioTrack

Source 

@DomName('SpeechRecognition.audioTrack')
@DocsEditable()
@Experimental() // untriaged
MediaStreamTrack get audioTrack =>
    _blink.BlinkSpeechRecognition.instance.audioTrack_Getter_(this);
void audioTrack=(MediaStreamTrack value)

Source 

@DomName('SpeechRecognition.audioTrack')
@DocsEditable()
@Experimental() // untriaged
set audioTrack(MediaStreamTrack value) =>
    _blink.BlinkSpeechRecognition.instance.audioTrack_Setter_(this, value);