How to correctly set the base locale in htaccess for localhost?

Question

Apache HTTP Server

Suddenly got ambushed. There is a bilingual project. On hosting, it works great with the formation of English-language pages using the en/ pseudo-directory. However, on localhost, the same htaccess directives give errors and are not executed. Those. rules like this don't work:

RewriteRule ^en/(.*)$ http://localhost/site/$1 [QSA,L]

I suspect that RewriteBase /. How to fix?