text: const synthesis = window.speechSynthesis;
  const synthesisText = document.querySelector('#synthesisText');
  
  function speak(){
    const utter = new SpeechSynthesisUtterance(synthesisText.value);
    // the list of all available voices
    const voices = synthesis.getVoices();
    
    for(i = 0; i < voices.length; ++i) {
      if(voices[i].name === "Google 國語（臺灣）") {
        utter.voice = voices[i];
      }
    }
    
    utter.rate = 1;
    utter.pitch = 1;
    synthesis.speak(utter);
  }