mod_rewrite is a powerful and sophisticated Apache web server module that allows urls to be rewritten using regular expressions. To redirect the urls to the corresponding url with www in front:
Put on on your webserver config
Centos / Fedora / RHEL: /etc/httpd/conf/httpd.conf
Debian / Ubuntu: /etc/apache2/apache2.conf
RewriteEngine On
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^(es|fr|de).
RewriteCond %{HTTP_HOST} (^[^w]{3}[^.].*)$ [NC]
RewriteRule ^.*$ http://www.%1%{REQUEST_URI} [L,NE]
Note that the second rule allows you to define urls to which the general rule will not apply, therefore all the urls that start with es., de., de. will be excluded from redirection
Later put on your VirtualHost or in the .htaccess
RewriteEngine On
RewriteOptions Inherit