SpeechSynthesisUtterance function finally works for Chinese on iOS, Android and Safari Mac.

SpeechSynthesisUtterance function finally works on iOS, Android and Safari Mac.
https://github.com/lookang/codesforejss/blob/master/function%20speech%20()
example
https://iwant2study.org/ospsg/index.php/855

You may modify the code accordingly

// copy this custom function

                   // add the speech(option) on a play button for iOS

function speech (option) {

try { // allow code to run in Student Learning Space 

var parent = parent.cordova;

if(parent) { // check it is running in Android or iOS

        parent.TTS.speak(option, function () {          

        }, function (reason) {          

        });

    }

    }

    catch(e) {

      var parent=false;

  var msg = new SpeechSynthesisUtterance(option);

  //https://stackoverflow.com/questions/43983845/speechsynthesis-api-for-chinese-firefox

  // Set the text.

//msg.text = option; 

//https://forums.developer.apple.com/message/323564#323564

msg.voice = speechSynthesis.getVoices().filter(function(voice) { return voice.name == 'Ting-Ting'; })[0];

msg.lang = 'zh-CH'; // need for android 

//https://flaviocopes.com/speech-synthesis-api/

//debug

//console.log(`Voices #: ${speechSynthesis.getVoices().length}`)

//speechSynthesis.getVoices().forEach(voice => {

// console.log(voice.name, voice.lang)

//})

//debug

// Queue this utterance.

window.speechSynthesis.speak(msg);

}

}