Rick Curran

WordPress 5.9 added a new language selector to allow users to switch languages from a dropdown on the login screen if more than one language is enabled on your WordPress installation. This plugin provides a quick and easy way to prevent this language selector from appearing.
It is a very simple plugin which is provided for ease of use: you need only to install and activate the plugin and it will prevent the language dropdown from appearing on the login screen of your site.
Alternatively, you can also achieve the same effect by adding the following line of code to the <code>functions.php</code> file in your theme:
<pre><code>add_filter( 'login_display_language_dropdown', '__return_false' );
</code></pre>

Disable Login Language Selector

Remove the language selector from the login screen if you have more than one language enabled in WordPress 5.9 and later.

theode

Did you ever struggle with more than one language on a WordPress blog? 
In a world of globalization those struggles reach me very often.
This plugin has the ability to store language codes the in post meta data to have articles with different languages on the same page. This might be interesting for blogs who only need sometimes a different language.
One of those is the following case: 
The boss is writing articles in english but its a german company and needs some articles in german too. 
But the second language articles are unique and not only translations.
You maybe think that would be quite simple using WPML. But what are you doing if you need both languages on the start page? 
For this special case, we wrote a plugin, which is able to show all languages on the home page and manipulates the query if some language is chosen. 
It also makes a difference in terms of SEO as it changes the line
<html xmlns=”http://www.w3.org/1999/xhtml” dir=”ltr” lang=”en-EN”>
according to your language.
For a real working experience you can use it in combination with the <a href="https://wordpress.org/extend/plugins/no-function-language-widget/" title="no function language widget" rel="ugc">no function language widget</a>.

Language Field

If you don't need a full multilingual plugin, but have single articles in a different language.

Disable Login Language Selector vs Language Field