Disable the language dropdown on the login page as it may confuse some users/admins.
WordPress 5.9 introduced a language switcher on the login page. I saw it on a site I maintain as a volunteer. I know that the other site admins could be confused by this new item on the login page so I looked at how to disable it.
A one line plugin
Before reading the above article I searched the WordPress 5.9 source for the language switcher (I found the ‘language-switcher’ ID in the login page markup. The switcher code is in wp-login.php. I then found a simple filter (I love filters!) that I could use to disable it:
apply_filters( 'login_display_language_dropdown', true )
Returning ‘false’ will disable the language switcher. With the ‘__return_false‘ the plugin code will be one line!
I wrote the mini plugin before reading the make.wordpress.org article where it has the exact same line that I use. It was the most obvious solution.