JSFiddle - React, Tailwind, and code Playground

JavaScript

let finalTranscript = '';
let recognition = new window.webkitSpeechRecognition();
recognition.interimResults = true;
recognition.continuous = true;
recognition.onresult = (event) => {
  let interimTranscript = '';
  for (let i = event.resultIndex, len = event.results.length; i < len; i++) {
    let transcript = event.results[i][0].transcript;
    if (event.results[i].isFinal) {
      finalTranscript += transcript;
    } else {
      interimTranscript += transcript;
    }
  }
  console.log(finalTranscript, interimTranscript);
}
recognition.start();