Hi Benna try this:
// Labels loading, after that $newsletter_labels is filled
$newsletter_labels = null;
if (isset($_GET['lang'])) $lang_ecom_qtrans = $_GET['lang'];
else $lang_ecom_qtrans = $_COOKIE['qlang_ecom_lang'];
if($lang_ecom_qtrans != ''){
$lang = '';
switch($lang_ecom_qtrans){
case 'en':
$lang = 'en_US.php';
break;
case 'es':
$lang = 'it_IT.php';
break;
case 'ru':
$lang = 'ru_RU.php';
break;
// add cases for the langs youre using
}
require(dirname(__FILE__).'/languages/'.$lang);
} else if(get_option('language_setting') != '') {
require(dirname(__FILE__).'/languages/'.get_option('language_setting'));
} else {
require(dirname(__FILE__).'/languages/en_US.php');
}
@include_once(ABSPATH . 'wp-content/plugins/newsletter-custom/languages/en_US.php');
if (WPLANG != '') @include_once(ABSPATH . 'wp-content/plugins/newsletter-custom/languages/' . WPLANG . '.php');