So I have been trying to get this for a thing I am doing but couldn't find any good tutorials on it or questions on it here. All I found was people finding out how to highlight the text with a textarea. In my code the last two params for the function are for the text that displays the current text that is being read.

function speak(text, speed, displaytext, idoftexttodisplay) {
    let realspeed = undefined

    if (speed) {
        realspeed = speed
    } else {
        realspeed = 1
    }

    let speech = new SpeechSynthesisUtterance(text)
    speech.lang = "en"
    speech.rate = realspeed
    speechSynthesis.speak(speech)
}