Nope just an issue with your .htacess rewrite rules I think
Try this
RewriteRule ^/?$ en/ [R,L] # redirect to language of your choice
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(en|de)/(.*?/)?([A-Za-z0-9_-]+)/?$ index.php?id=$3&lang=$1 [QSA,L]
RewriteRule ^(en|de)/?$ index.php?lang=$1 [QSA,L] # handle index page without 'index'
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule /?([A-Za-z0-9_-]+)/?$ index.php?id=$1 [QSA,L]
or this
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^/?$ en/ [R,L] # redirect to language of your choice
RewriteRule ^(en|de)/(.*)$ $2?lang=$1 [QSA,DPI] # replace with your languages
RewriteRule ^(.*);(\d+)([^\d/][^/]*)?/?$ $1$3?page=$2 [QSA,DPI] # for use with pagify plugin
RewriteRule /?([A-Za-z0-9_-]+)/?$ index.php?id=$1 [QSA,L]
RewriteRule ^ index.php [L] # for everything else show home page
Try this
RewriteRule ^/?$ en/ [R,L] # redirect to language of your choice
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(en|de)/(.*?/)?([A-Za-z0-9_-]+)/?$ index.php?id=$3&lang=$1 [QSA,L]
RewriteRule ^(en|de)/?$ index.php?lang=$1 [QSA,L] # handle index page without 'index'
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule /?([A-Za-z0-9_-]+)/?$ index.php?id=$1 [QSA,L]
or this
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^/?$ en/ [R,L] # redirect to language of your choice
RewriteRule ^(en|de)/(.*)$ $2?lang=$1 [QSA,DPI] # replace with your languages
RewriteRule ^(.*);(\d+)([^\d/][^/]*)?/?$ $1$3?page=$2 [QSA,DPI] # for use with pagify plugin
RewriteRule /?([A-Za-z0-9_-]+)/?$ index.php?id=$1 [QSA,L]
RewriteRule ^ index.php [L] # for everything else show home page
Todo arde si le aplicas la chispa adecuada.