title: Change language on wordpress site
body: <p>Im trying to create a button in my wordpress theme that changes the sites language. I have followed the guide (<a href="https://developer.wordpress.org/themes/functionality/internationalization" rel="nofollow noreferrer">https://developer.wordpress.org/themes/functionality/internationalization</a>), created filed in poedit etc and loaded the text-domain in functions.php.</p>
  
  <p>But how can i now change the language on the site?</p>
  
  <p>functions.php</p>
  
  <pre><code>public function theme_supports() {
      load_theme_textdomain( 'marcial', get_template_directory() . '/languages' );
  }
  </code></pre>
  
  <p>style.css</p>
  
  <pre><code>/**
  * Theme Name: marcial
  * Description: lorem ipsum
  * Author: lorem ipsum
  * Text Domain: marcial
  * Domain Path: /languages
  */
  </code></pre>
  
  <p>header.php (render test), it works</p>
  
  <pre><code>__('hello', 'marcial')
  </code></pre>
  
  <p>It prints what in my pot-file. But how can i change language?</p>