.htaccess file redirect problem

Hello!

If someone is entering a webpage or folder that doesn't exist on the webpage like for example those:

www.website.nu/en/

www.website.nu/sv/

www.website.nu/page.aspx

I now wonder what we need to add in the .htaccess file to redirect NON existing pages that gives the: "HTTP Error 404.0 - Not Found" towww.website.nu

My .htaccess file is located in the very root folder in the hosting. So "website" is a subdirectory.

Thank you!