.htaccess language detection, redirect and friendly URLs [closed]

Question

I'm having problems with my .htaccess file.

RewriteEngine On
RewriteCond %{HTTP:Accept-Language} (fr) [NC]
RewriteRule .* http://www.example.com/frans [R,L]
RewriteRule .* http://www.example.com/nederlands [R,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^(.+)$ $1.html [L,QSA]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*\.html\ HTTP/
RewriteRule ^(.*)\.html$ /$1 [R=301,L]

Can anyone please help?

I want it to detect the browser language of the client, then redirect French to /frans, and all other languages to /nederlands.

Also I want to show the URLs without .html or .php at the end, so clean URLs.