How to use SpeechSynthesisUtterance() and window.speechSynthesis.speak() at chromium browser?
var msg = new SpeechSynthesisUtterance( "Hello I am browser" );
window.speechSynthesis.speak( msg );
yields no output at system speakers.
Issues with the API have bee noted The HTML5 SpeechSynthesis API is rubbish;
var voices = window.speechSynthesis.getVoices();
logs an empty array for voices identifier; and only chrome not chromium purportedly support Web Speech API Specification, the Web Speech API Demonstration sets value of html element at demonstration to utterance voiced when microphone is enabled at page.
At least some of the JavaScript relating to the functionality is apparently
var langs =
[['Afrikaans', ['af-ZA']],
['Bahasa Indonesia',['id-ID']],
['Bahasa Melayu', ['ms-MY']],
['Català', ['ca-ES']],
['?e?tina', ['cs-CZ']],
['Dansk', ['da-DK']],
['Deutsch', ['de-DE']],
['English', ['en-AU', 'Australia'],
['en-CA', 'Canada'],
['en-IN', 'India'],
['en-NZ', 'New Zealand'],
['en-ZA', 'South Africa'],
['en-GB', 'United Kingdom'],
['en-US', 'United States']],
['Espa?ol', ['es-AR', 'Argentina'],
['es-BO', 'Bolivia'],
['es-CL', 'Chile'],
['es-CO', 'Colombia'],
['es-CR', 'Costa Rica'],
['es-EC', 'Ecuador'],
['es-SV', 'El Salvador'],
['es-ES', 'Espa?a'],
['es-US', 'Estados Unidos'],
['es-GT', 'Guatemala'],
['es-HN', 'Honduras'],
['es-MX', 'México'],
['es-NI', 'Nicaragua'],
['es-PA', 'Panamá'],
['es-PY', 'Paraguay'],
['es-PE', 'Perú'],
['es-PR', 'Puerto Rico'],
['es-DO', 'República Dominicana'],
['es-UY', 'Uruguay'],
['es-VE', 'Venezuela']],
['Euskara', ['eu-ES']],
['Filipino', ['fil-PH']],
['Fran?ais', ['fr-FR']],
['Galego', ['gl-ES']],
['Hrvatski', ['hr_HR']],
['IsiZulu', ['zu-ZA']],
['íslenska', ['is-IS']],
['Italiano', ['it-IT', 'Italia'],
['it-CH', 'Svizzera']],
['Lietuvi?', ['lt-LT']],
['Magyar', ['hu-HU']],
['Nederlands', ['nl-NL']],
['Norsk bokm?l', ['nb-NO']],
['Polski', ['pl-PL']],
['Português', ['pt-BR', 'Brasil'],
['pt-PT', 'Portugal']],
['Roman?', ['ro-RO']],
['Sloven??ina', ['sl-SI']],
['Sloven?ina', ['sk-SK']],
['Suomi', ['fi-FI']],
['Svenska', ['sv-SE']],
['Ti?ng Vi?t', ['vi-VN']],
['Türk?e', ['tr-TR']],
['Ελληνικ?', ['el-GR']],
['български', ['bg-BG']],
['Pусский', ['ru-RU']],
['Српски', ['sr-RS']],
['Укра?нська', ['uk-UA']],
['???', ['ko-KR']],
['中文', ['cmn-Hans-CN', '普通话 (中国大陆)'],
['cmn-Hans-HK', '普通话 (香港)'],
['cmn-Hant-TW', '中文 (台灣)'],
['yue-Hant-HK', '粵語 (香港)']],
['日本語', ['ja-JP']],
['??????', ['hi-IN']],
['???????', ['th-TH']]];
for (var i = 0; i < langs.length; i++) {
select_language.options[i] = new Option(langs[i][0], i);
}
select_language.selectedIndex = 7;
updateCountry();
select_dialect.selectedIndex = 6;
showInfo('info_start');
function updateCountry() {
for (var i = select_dialect.options.length - 1; i >= 0; i--) {
select_dialect.remove(i);
}
var list = langs[select_language.selectedIndex];
for (var i = 1; i < list.length; i++) {
select_dialect.options.add(new Option(list[i][1], list[i][0]));
}
select_dialect.style.visibility = list[1].length == 1 ? 'hidden' : 'visible';
}
var create_email = false;
var final_transcript = '';
var recognizing = false;
var ignore_onend;
var start_timestamp;
if (!('webkitSpeechRecognition' in window)) {
upgrade();
} else {
start_button.style.display = 'inline-block';
var recognition = new webkitSpeechRecognition();
recognition.continuous = true;
recognition.interimResults = true;
recognition.onstart = function() {
recognizing = true;
showInfo('info_speak_now');
start_img.src = '/intl/en/chrome/assets/common/images/content/mic-animate.gif';
};
recognition.onerror = function(event) {
if (event.error == 'no-speech') {
start_img.src = '/intl/en/chrome/assets/common/images/content/mic.gif';
showInfo('info_no_speech');
ignore_onend = true;
}
if (event.error == 'audio-capture') {
start_img.src = '/intl/en/chrome/assets/common/images/content/mic.gif';
showInfo('info_no_microphone');
ignore_onend = true;
}
if (event.error == 'not-allowed') {
if (event.timeStamp - start_timestamp < 100) {
showInfo('info_blocked');
} else {
showInfo('info_denied');
}
ignore_onend = true;
}
};
recognition.onend = function() {
recognizing = false;
if (ignore_onend) {
return;
}
start_img.src = '/intl/en/chrome/assets/common/images/content/mic.gif';
if (!final_transcript) {
showInfo('info_start');
return;
}
showInfo('');
if (window.getSelection) {
window.getSelection().removeAllRanges();
var range = document.createRange();
range.selectNode(document.getElementById('final_span'));
window.getSelection().addRange(range);
}
if (create_email) {
create_email = false;
createEmail();
}
};
recognition.onresult = function(event) {
var interim_transcript = '';
if (typeof(event.results) == 'undefined') {
recognition.onend = null;
recognition.stop();
upgrade();
return;
}
for (var i = event.resultIndex; i < event.results.length; ++i) {
if (event.results[i].isFinal) {
final_transcript += event.results[i][0].transcript;
} else {
interim_transcript += event.results[i][0].transcript;
}
}
final_transcript = capitalize(final_transcript);
final_span.innerHTML = linebreak(final_transcript);
interim_span.innerHTML = linebreak(interim_transcript);
if (final_transcript || interim_transcript) {
showButtons('inline-block');
}
};
}
function upgrade() {
start_button.style.visibility = 'hidden';
showInfo('info_upgrade');
}
var two_line = /
/g;
var one_line = /
/g;
function linebreak(s) {
return s.replace(two_line, '<p></p>').replace(one_line, '<br>');
}
var first_char = /S/;
function capitalize(s) {
return s.replace(first_char, function(m) { return m.toUpperCase(); });
}
function createEmail() {
var n = final_transcript.indexOf('
');
if (n < 0 || n >= 80) {
n = 40 + final_transcript.substring(40).indexOf(' ');
}
var subject = encodeURI(final_transcript.substring(0, n));
var body = encodeURI(final_transcript.substring(n + 1));
window.location.href = 'mailto:?subject=' + subject + '&body=' + body;
}
function copyButton() {
if (recognizing) {
recognizing = false;
recognition.stop();
}
copy_button.style.display = 'none';
copy_info.style.display = 'inline-block';
showInfo('');
}
function emailButton() {
if (recognizing) {
create_email = true;
recognizing = false;
recognition.stop();
} else {
createEmail();
}
email_button.style.display = 'none';
email_info.style.display = 'inline-block';
showInfo('');
}
function startButton(event) {
if (recognizing) {
recognition.stop();
return;
}
final_transcript = '';
recognition.lang = select_dialect.value;
recognition.start();
ignore_onend = false;
final_span.innerHTML = '';
interim_span.innerHTML = '';
start_img.src = '/intl/en/chrome/assets/common/images/content/mic-slash.gif';
showInfo('info_allow');
showButtons('none');
start_timestamp = event.timeStamp;
}
function showInfo(s) {
if (s) {
for (var child = info.firstChild; child; child = child.nextSibling) {
if (child.style) {
child.style.display = child.id == s ? 'inline' : 'none';
}
}
info.style.visibility = 'visible';
} else {
info.style.visibility = 'hidden';
}
}
var current_style;
function showButtons(style) {
if (style == current_style) {
return;
}
current_style = style;
copy_button.style.display = style;
email_button.style.display = style;
copy_info.style.display = 'none';
email_info.style.display = 'none';
}
attributed to authors of the document.
Though not certain how this affects the usage of SpeechSynthesisUtterance() and window.speechSynthesis.speak()?
How to load voices to populate window.speechSynthesis.getVoices()?
How does the linked demonstration document implement the functionality to transcribe voice to text?
What are the workarounds necessary to use the Web Speech API at chromium browser?
Specifically, how to transcribe voice to text and convert text to audio output?
See Question&Answers more detail:
os 
