WordPress跳过语言包加载提高效率

<?php
/* 
Plugin Name: WPJAM Diff Lang
Plugin URI: http://blog.wpjam.com/m/setup-different-admin-and-frontend-language-on-wordpress/
Description:  WordPress 技巧：前后台设置不同语言
Version: 0.1
Author: denishua
Author URI: http://blog.wpjam.com/
*/

add_filter( 'locale', 'wpjam_locale' );
function wpjam_locale($locale) {
    $locale = ( is_admin() ) ? $locale : 'en_US';
    return $locale;
}