It is necessary to add a prefix for the site:
/ ru
that was:
site.com/ru/
well, and all the other links, respectively, to be the same with him:
site.com/ru/url1
site.com/ru/url2
Now using .htacces there is a string
RewriteRule ^ru/(([^/]+/)*[^.]+)$ /$1.php [L]
It allows you to access files through the / ru prefix, however, the main page is called only without a prefix, and when you try to turn it on as
site.com/ru/
gives 404