JSFiddle - React, Tailwind, and code Playground

HTML

<div lang='en'>
    <h1 class='en-only'>English</h1>
    <h1 class='de-only'>German</h1>
</div>

JavaScript

$(document).ready(function(){
    $('.en-only:not(:lang(en)),.de-only:not(:lang(de))').hide();
})