kami

I am using PHP 5.5 on windows 8 and I am trying to localize my website to multiple languages while everything is OK on remote host , the gettext function does not work correctly in my localhost. I have implemented the whole tutorial of http://www.sitepoint.com/localizing-php-applications-1/ step by step but it seems setlocale(LC_ALL, "en_US") fails and I don't know how to correct or install "en_US" in my system. when I use "en-US" instead of "en_US" the sellocale function does not return FALSE but again the gettext function return the original string.