CodePen Embed - Bajbxop

<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")
})

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