How do I change the language of only the login page?

Question

My wordpress blog is set up as de_DE. This means that my login page is also displayed in de_DE.

I would like to only have the login page in en_US.

So, How would I programmatically change a single page's language?

Note: I have WPML but I don't wish to use it, I only want to change one page on the whole site.

Answer 1

This will need to go in a plug-in, just put the following inside a file (login-languge.php) in wp-content/plugins/

/*
Plugin Name:  Log-in Language
Plugin URI:   http://wordpress.stackexchange.com/questions/72692/how-do-i-change-the-language-of-only-the-login-page
Description:  Changes the language for log-in/register screens only
Author:       Stephen Harris
Author URI:   http://stephenharris.info
Version:      1.0
License:      GNU GPL 2
*/
add_action('plugins_loaded', 'wpse72696_login_language_init');

function wpse72696_login_language_init(){
    if( in_array( $GLOBALS['pagenow'], array( 'wp-login.php', 'wp-register.php' ) ) ){
        add_filter('locale', 'wpse72692_login_language',10);
    }
}

function wpse72692_login_language( $locale ){
    return 'en_US';
}

Answer 2

You can repalce define( 'WPLANG', 'de_DE'); in your wp-config.php by this code structuer.

if (basename(parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH)) == 'wp-login.php'){
    define( 'WPLANG',  'en_US');
} else {
    define( 'WPLANG',  'de_DE');
}

Answer 3

Another way you can do this in your functions.php using unload_textdomain($domain)

add_action('init', 'remove_login_translation');
function remove_login_translation() {
    if( in_array( $GLOBALS['pagenow'], array( 'wp-login.php', 'wp-register.php' ) ) ) {
        unload_textdomain('default');
    }
}