resume()

let synth = window.speechSynthesis;

let utterance1 = new SpeechSynthesisUtterance('How about we say this now? This is quite a long sentence to say.');
let utterance2 = new SpeechSynthesisUtterance('We should say another sentence too, just to be on the safe side.');

synth.speak(utterance1);
synth.speak(utterance2);

synth.pause(); // pauses utterances being spoken
synth.resume() // resumes speaking