使用百分比字符重定向变量url

I am currently working on my website where I've found some weird urls. I am trying to redirect (301) url's to the correct url but I cannot figured out how to correctly redirect those url's in .htaccess.

e.g. old url

/slug/variable-%language%.html

Al those urls should redirect to

/slug/variable-english.html

Where 'variable' can have different values (also with an '-' separator included.

Many thanks!

Something like this:

Redirect 301  /slug/variable-english.html  http://www.domain.com/slug/variable-english.html
Redirect 301  /slug/variable-chinese.html  http://www.domain.com/slug/variable-chinese.html

Why can you not just redirect to new domain as the rest of the urls is the same?

RewriteEngine on
RewriteCond %{HTTP_HOST} ^example-old\.com$ [NC]
RewriteRule ^(.*)$ http://www.example-new.com/$1 [R=301,L]