choosevoice.js

//cut down from https://github.com/mdn/web-speech-api/tree/master/speak-easy-synthesis

var synth = window.speechSynthesis;

var voiceSelect = document.querySelector('select');

var voices = [];

function populateVoiceList() {
  voices = synth.getVoices();
  var selectedIndex = voiceSelect.selectedIndex < 0 ? 0 : voiceSelect.selectedIndex;
  voiceSelect.innerHTML = '';
  for(i = 0; i < voices.length ; i++) {
    var option = document.createElement('option');
    option.textContent = voices[i].name + ' (' + voices[i].lang + ')';
    
    if(voices[i].default) {
      option.textContent += ' -- DEFAULT';
    }

    option.setAttribute('data-lang', voices[i].lang);
    option.setAttribute('data-name', voices[i].name);
    voiceSelect.appendChild(option);
  }
  voiceSelect.selectedIndex = selectedIndex;
}

populateVoiceList();
if (speechSynthesis.onvoiceschanged !== undefined) {
  speechSynthesis.onvoiceschanged = populateVoiceList;
}