I18N change default frontend language

[Alb]

I have searched and search in the forum and internet how to change the default frontend language but I can't find nothing. My site has 4 languages:
EN,AL,RO,IT and the default language is set to EN. I tried to change from admin the language to sq but without success and is to complicated to rename all the pages.
I was wondering if I can make a SESSION before the site loads for the first time in a browser .
SESSION starts when the site is loaded and set the language to AL and the site loads,Then the SESSION stops because I don't want to set e session each time I load the page. Am I in the right direction or I should use cookies.
I am not an expert in PHP but I am trying to find a solution
Anyone can help me with a logic direction or code?
Thanks in advance

[Alb]

I think I found a solution for this problem. What I did is uncomment in gsconfig

PHP Code:

#define('I18N_IGNORE_USER_LANGUAGE',true); 


and then edit in frontend.class.php from

PHP Code:

public static function getLanguages() {
    if (!self::$languages) {
      self::$languages = array();
      if (isset($_GET[I18N_LANGUAGE_PARAM])) {
        self::$languages[] = $_GET[I18N_LANGUAGE_PARAM];
      }
      if (isset($_SESSION[I18N_LANGUAGE_KEY]) && !in_array($_SESSION[I18N_LANGUAGE_KEY],self::$languages)) {
        self::$languages[] = $_SESSION[I18N_LANGUAGE_KEY];
      }
      if (!defined('I18N_IGNORE_USER_LANGUAGE') || !I18N_IGNORE_USER_LANGUAGE) {
        $httplanguages = explode(",", @$_SERVER['HTTP_ACCEPT_LANGUAGE']);
        foreach ($httplanguages as $language) {
          $language = substr($language,0,2);
          if (!in_array($language,self::$languages)) self::$languages[] = $language;
        }
      } 


to

PHP Code:

public static function getLanguages() {
    if (!self::$languages) {
      self::$languages = array();
      if (isset($_GET[I18N_LANGUAGE_PARAM])) {
        self::$languages[] = $_GET[I18N_LANGUAGE_PARAM];
      }
      if (isset($_SESSION[I18N_LANGUAGE_KEY]) && !in_array($_SESSION[I18N_LANGUAGE_KEY],self::$languages)) {
        self::$languages[] = $_SESSION[I18N_LANGUAGE_KEY];
      }
      if (!defined('I18N_IGNORE_USER_LANGUAGE') || !I18N_IGNORE_USER_LANGUAGE) {
        $httplanguages = explode(",", @$_SERVER['HTTP_ACCEPT_LANGUAGE']);
        foreach ($httplanguages as $language) {
          $language = "sq";
          if (!in_array($language,self::$languages)) self::$languages[] = $language;
        }
      } 


and now my default language is albanian. You see any problem/ risk in this modification ?
Thanks