PHP: Detect browser language

If your website is multilingual, it can be useful to detect the browser language to use this language as the default. The code below will return the language used by the client’s browser.

function get_client_language($availableLanguages, $default='en'){

 if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {

  $langs=explode(',',$_SERVER['HTTP_ACCEPT_LANGUAGE']);

  foreach ($langs as $value){

   $choice=substr($value,0,2);

   if(in_array($choice, $availableLanguages)){

    return $choice;

   }

  }

 } 

 return $default;

}