我可以通过添加以下内容来覆盖多站点通知电子邮件：

remove_filter(\'wpmu_signup_user_notification_email\',\'admin_created_user_email\');
add_filter(\'wpmu_signup_user_notification_email\',<function_name_here>);
add_filter(\'wpmu_signup_user_notification\',<function_name_here>);
add_filter(\'wpmu_signup_user_notification_subject\',<function_name_here>);

@user2647似乎走上了正确的道路，但我认为这更正确：

remove_action( \'wpmu_new_user\', \'newuser_notify_siteadmin\' );
add_action( \'wpmu_new_user\', \'my_notification\' );

function my_notification ($user_id) {
  // Make your custom notification here.
}

remove_filter 没有效果，因为/wp admin/user new。php运行

add_filter(\'wpmu_signup_user_notification_email\', admin_created_user_email);

我通过添加一个优先级较低（数字较高）的新过滤器来实现这一点，因此它在admin_created_user_email, 具有默认优先级（10）的：

function reset_admin_email(){
    add_filter( \'wpmu_signup_user_notification_email\', \'admin_created_user_email2\', 11 );
}

这种事情行得通吗？

if ( !function_exists(\'wp_new_user_notification\') ) {
function wp_new_user_notification( $user_id, $plaintext_pass = \'\' ) {
    $user = new WP_User($user_id);

    $user_login = stripslashes($user->user_login);
    $user_email = stripslashes($user->user_email);
            $message = $user_login . " " . $user_email;

    wp_mail($user_email, sprintf(__(\'[%s] Your username and password\'), get_option(\'blogname\')), $message);

}
}

Dylan 答案正确，但需要详细说明。

添加一个在默认过滤器之后使用高于10的优先级触发的过滤器：

add_filter( \'wpmu_signup_user_notification_email\', \'wp_new_user_notification\', 11 );

function wp_new_user_notification( $user_id, $plaintext_pass = \'\' ) {

            $user = new WP_User( $user_id );

            $user_login = stripslashes( $user->user_login );
            $user_email = stripslashes( $user->user_email );

            $message  = sprintf( __(\'New user registration on %s:\'), get_option(\'blogname\') ) . "\\r\\n\\r\\n";
            $message .= sprintf( __(\'Username: %s\'), $user_login ) . "\\r\\n\\r\\n";
            $message .= sprintf( __(\'E-mail: %s\'), $user_email ) . "\\r\\n";

            @wp_mail(
                get_option(\'admin_email\'),
                sprintf(__(\'[%s] New User Registration\'), get_option(\'blogname\') ),
                $message
            );

            if ( empty( $plaintext_pass ) )
                return;

            $message  = __(\'Hi there,\') . "\\r\\n\\r\\n";
            $message .= sprintf( __("Welcomeeee to %s! Here\'s how to log in:"), get_option(\'blogname\')) . "\\r\\n\\r\\n";
            $message .= wp_login_url() . "\\r\\n";
            $message .= sprintf( __(\'Username: %s\'), $user_login ) . "\\r\\n";
            $message .= sprintf( __(\'Password: %s\'), $plaintext_pass ) . "\\r\\n\\r\\n";
            $message .= sprintf( __(\'If you have any problems, please contact me at %s.\'), get_option(\'admin_email\') ) . "\\r\\n\\r\\n";
            $message .= __(\'Adios!\');

            wp_mail(
                $user_email,
                sprintf( __(\'[%s] Yourrrrrrr username and password\'), get_option(\'blogname\') ),
                $message
            );
        }

这些电子邮件中的大部分文本都是可翻译的，这意味着我们可以利用WP的gettext 滤器我在网上找到了以下实现翻译的方法，但找不到原始源代码。

首先定义过滤器挂钩：

add_filter(\'gettext\', [new AddAction(), \'gqa_text_strings\'], 20, 3);

 /**
 * Change a few text strings related to the login/registration process
 *
 * @link http://codex.wordpress.org/Plugin_API/Filter_Reference/gettext
 *
 * @param $translated_text
 * @param $text
 * @param $domain
 *
 * @return string
 */
function gqa_text_strings($translated_text, $text, $domain)
{
    switch ( $translated_text ) {
        case \'Get your own %s account in seconds\' :
            $translated_text = __(\'Request access to %s\', \'gqa\');
            break;
        case \'We send your registration email to this address. (Double-check your email address before continuing.)\' :
            $translated_text = __(\'\', \'gqa\');
            break;
        case \'But, before you can start using your new username, <strong>you must activate it</strong>.\' :
            $translated_text = __(\'An email with login instructions has been sent to the address you provided.\', \'gqa\');
            break;
        case "Check your inbox at %s and click the link given." :
            $translated_text = __(\'Check your inbox at %s.\', \'gqa\');
            break;
        case \'If you do not activate your username within two days, you will have to sign up again.\' :
            $translated_text = __(\'\', \'gqa\');
            break;
        // Subject line for new user registration email
        case \'New %1$s User: %2$s\' :
            $translated_text = __(\'Your account information\');
            break;
        // Error message when registering a new account with an already used username.
        case \'That username is currently reserved but may be available in a couple of days.\' :
            $translated_text = __(\'A user with that username already exists. Do you already have an account? Please contact site administrators or try again.\');
            break;
        // Error message when registering a new account with an already used email address.
        case \'That email address has already been used. Please check your inbox for an activation email. It will become available in a couple of days if you do nothing.\' :
            $translated_text = __(\'That email address has already been assigned to an account. Do you already have an account? Please contact site administrators or try again\');
            break;
    }

    return $translated_text;
}

case \'Hi, You\\\'ve been invited to join \\\'%1$s\\\' at
%2$s as a %3$s. If you do not want to join this site please ignore
this email. This invitation will expire in a few days. Please click the following link to activate your user account: %%s\' :
    $translated_text = __(\'Whatever you want the email to say\', \'gqa\');
    break;