.htaccess making a fake subfolder after main domain - .htaccess

Question

I want/need to rewrite all my product urls
for example a product url in three languages.
mainurl.com/en/outdoor/wood-table
mainurl.com/de/außenbereich/holz-tisch
mainurl.com/it/esterno/tavolo-legno
What url i want/need is:
mainurl.com/products/en/outdoor/wood-table
mainurl.com/products/de/außenbereich/holz-tisch
mainurl.com/products/it/esterno/tavolo-legno
Running the Shop Local with xampp in the Root-Folder htdocs.
How can i rewrite this url via .htaccess and making this fake subfolder after the mainurl?
This is the original .htaccess file that is included in the Shopsystem xt:commerce:
# RewriteEngine on
# RewriteRule !\.(js|ico|gif|jpg|png|css)$ index.php
DirectoryIndex index.php
<IfModule mod_rewrite.c>
SetEnv HTTP_MOD_REWRITE On
Options -MultiViews
RewriteEngine on
RewriteCond %{REQUEST_URI} !^/media/
RewriteCond %{REQUEST_URI} !^/xtAdmin/
RewriteCond %{REQUEST_URI} !^/skin/
RewriteCond %{REQUEST_URI} !^/js/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule .* index.php
</IfModule>
<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType image/x-icon "access plus 2692000 seconds"
ExpiresByType image/jpeg "access plus 2692000 seconds"
ExpiresByType image/png "access plus 2692000 seconds"
ExpiresByType image/gif "access plus 2692000 seconds"
ExpiresByType application/x-shockwave-flash "access plus 2692000 seconds"
ExpiresByType text/css "access plus 2692000 seconds"
ExpiresByType text/javascript "access plus 2692000 seconds"
ExpiresByType application/x-javascript "access plus 2692000 seconds"
</IfModule>
<IfModule mod_headers.c>
<FilesMatch "\\.(ico|jpe?g|png|gif|swf|css|js)$">
Header set Cache-Control "max-age=2692000, public"
</FilesMatch>
Header unset ETag
Header unset Last-Modified
</IfModule>

Answer 1

Insert this rule just below RewriteEngine on:
RewriteRule ^product/(.*) $1 [L,NC]