1. @DomName('SpeechSynthesis.speak')
  2. @DocsEditable()
void speak(SpeechSynthesisUtterance utterance)

Source 

@DomName('SpeechSynthesis.speak')
@DocsEditable()
void speak(SpeechSynthesisUtterance utterance) =>
    _blink.BlinkSpeechSynthesis.instance.speak_Callback_1_(this, utterance);