Problems with localization

I’m creating a plugin and I’ve put:

define ('WPLANG', 'it_IT');

into wp-config.php file.

After plugin Name in the Header of the Plugin declaration:

* Text Domain: endpoint
* Domain Path: /languages/

For the load domain:

add_action( 'plugins_loaded', 'myplugin_load_textdomain' );

function myplugin_load_textdomain() {
    load_plugin_textdomain( 'endpoint', false, dirname(  __FILE__  ) . '/languages/' ); 
}

In languages I created pot, po and mo file with this names: end-point.pot, end-point-it_IT.po and end-point-it_IT.mo.

I switched to Italian but nothing is changed.

Any help?

1) Presuming you’re running WordPress 4.x. The WPLANG constant does nothing. WordPress 3 and below defined the default language in wp-config.php but since WordPress 4 setting your site language is done via the General Settings page in your admin area. Go to Settings > General and scroll to the bottom where is says “Site Language” next to a dropdown list.

2) The argument dirname(__FILE__).'/languages/' is wrong as this should be a relative path. Use dirname(plugin_basename(__FILE__)).'/languages/'