Simple class to check a client language from the HTTP headers

LangCheck.php

<?php

  class LangCheck
  {
    private $default;
    private $available;

    /**
     * @param array $available An array containing the available locales
     * @param string $default The default language in case none is found
     */
    public function __construct($available = ['es'], $default = 'es')
    {
      $this->default = $default;
      $this->available = $available;
    }

    /**
     * @return string Either the language stored on the cookie or Default
     */
    private function cookie() {
      if(isset($_COOKIE['preferred_language'])) {
        $preferred = $_COOKIE['preferred_language'];
        if(in_array($preferred, $this->available)) {
          return $preferred;
        }
      }
      return "Default";
    }

    /**
     * The header is sent by most of the modern browsers, it looks something
     * like this en-US,en;q=0.8,es;q=0.6, I ignore the q value because it's
     * implicitly ordered by the browser
     *
     * @param string $header The HTTP header HTTP_ACCEPT_LANGUAGES from
     *                       the global $_SERVER array
     * @return string The 2 letter language identifier
     */
    public function get($header = "")
    {
      $regex = '/([a-zA-Z]{2});/';
      $languages = [];
      preg_match_all($regex, $header, $languages);
      if($this->cookie() != 'Default') {
        return $this->cookie();
      }
      foreach($languages[1] as $language) {
        if(in_array($language, $this->available)) {
          return $language;
        }
      }
      return $this->default;
    }
  }