You can do something like:
const pauseBetweenWords = 3000; //ms
const sentences = [
'Word1, Word2, Word3',
'Word4, Word5, Word6',
'Word7, Word8, Word9'
];
const words = sentences.map(e => e.split(' '));
let currentIndices = sentences.map(e => 0);
$w.onReady(() => {
const elements = [$w('#text1'), $w('#text2'), $w('#text3')];
setInterval(showText, pauseBetweenWords);
function showText() {
elements.forEach((e, i) => {
let text;
currentIndices[i] === 0 ? text = '' : text = e.text;
e.text = text + words[i][currentIndices[i]];
currentIndices[i] = (currentIndices[i] + 1) % words[i].length;
});
}
})