How to display "Not Found" instead of automatic redirecting?

Question

how to redirect to 404 in .htaccess file ? Example

www.domain.com/ja/any_post or www.domain.com/ja/all_posts
www.domain.com/fr/any_post or www.domain.com/fr/all_posts

A little bit more explaining can't hurt. Example:

My original post is on URL www.domain.com/post.

I had japanese translation of it at this URL: www.domain.com/ja/post.
And also French translation: www.domain.com/fr/post.

I had to delete these translated posts and now when I type www.domain.com/ja/post to my address bar manually, URL is redirected automatically to original post at www.domain.com/post. The same goes for /fr/.

I need URL to stay www.domain.com/ja/post and show "Not found" for all posts (with /ja/ and /fr/ in URL) without using 301 to 404.php.

Here's my htaccess (WordPress):

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

Another thing I forgot to point out.../ja/ and /fr/ don't really exist.

Answer 1

The simplest method would be:

# Redirect to HTTP 404 File/Page Not Found
Redirect 404 "/ja/any_posts"
Redirect 404 "/ja/all_posts"
Redirect 404 "/fr/any_posts"
Redirect 404 "/fr/all_posts"

Though you could also use:

# Redirect to HTTP 404 File/Page Not Found
RewriteRule ^ja/any_posts$ - [R=404,L]
RewriteRule ^ja/all_posts$ - [R=404,L]
RewriteRule ^fr/any_posts$ - [R=404,L]
RewriteRule ^fr/all_posts$ - [R=404,L]

Or this can be written more efficiently as:

RewriteRule ^(fr|ja)/(all|any)_posts$ - [R=404,L]

Or if you meant to redirect every page in those subfolders then:

RewriteRule ^(fr|ja)/(.*?)$ - [R=404,L]

Edited following comments:

RewriteEngine On
RewriteBase /
RewriteRule ^(fr|ja)/(.*?)$ - [R=404,L]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

Answer 2

Something along these lines might do what you want. This will redirect the user to the 'main' version of the page, and add a 404 header in the process, removing the old link:

RewriteCond %{REQUEST_URI} ^/(ja|fr)/
RewriteRule ^(ja|fr)/(.*?) /$2 [L, R=404]