title: Polylang language switcher - show only language codes
body: <p>I created a menu inside a theme I'm creating and have added a language switcher that comes with Polylang.</p>
  
  <p>On the fronted the switcher shows up as it should, but it shows the full name of the language (eg. English, Deutsch,...). Instead of full names, I would like <strong>country codes</strong> to be printed.</p>
  
  <p>Now:</p>
  
  <p><a href="https://i.stack.imgur.com/14DQQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/14DQQ.png" alt="enter image description here"></a></p>
  
  <p>Wanted result:</p>
  
  <p><a href="https://i.stack.imgur.com/tmT9e.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tmT9e.png" alt="enter image description here"></a></p>