speech_synth.js

const talk = (optText) => {
  let text = optText || Array.from(document.querySelectorAll('p')).map(p => p.outerText).join(' ');
  let t2s = new SpeechSynthesisUtterance(text);
  let voices = window.speechSynthesis.getVoices();
  t2s.voice = voices.filter(v => v.name === 'Samantha')[0]; // Samantha is the standard US voice and lives at index 32 when I call this for my browser. Your locale may change this ordering.
  t2s.onend = function(e) { console.log('Read in ' + e.elapsedTime + ' seconds'); };
  window.speechSynthesis.speak(t2s);
};

// You can stop the output by calling...
const pause = () => window.speechSynthesis.paused ? window.speechSynthesis.resume() : window.speechSynthesis.pause();
const stop = () => window.speechSynthesis.cancel();