<div id="ru" class="item-lang">ru</div>
<div id="eng" class="item-lang">eng</div>
<div id="de" class="item-lang">de</div>
.selected {
  color: red
}
$(".item-lang").click(function() {
  $(".item-lang").removeClass("selected")
  $(this).addClass("selected")
})

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js