Asumaru

“Multisite Language Switcher” is very attractive plugin. 
However, It may not be available for your site plan.
<ul>
<li>Site A (English) example-site.com/</li>
<li>Site A (Japanese) example-site.com/jp/</li>
<li>Site B (English) example-site.com/siteB/</li>
<li>Site B (Japanese) example-site.com/siteB-jp/</li>
<li>Site C (English) example-site.com/siteC/</li>
<li>Site C (Japanese) example-site.com/siteC-jp/</li>
</ul>
“Multisite Language Switcher” cannot tell the difference between site A, site B and site C. 
Therefore you cannot connect the language when there are site A, site B, site C.
“MSLS Grouping” adds “group_key” to settings of “Multisite Language Switcher”. 
For example, you set “group_key” with “SiteA” or “SiteB” or “SiteC”. 
You can limit a language site in a group by doing this plugin. 
You can display only the first site when there are multiple same language sites in a group.
And, it provide shortcode “SameLangSites” and widget “SameLangSites”. 
You can output the list of different groups of the same language. 
For example, “SameLangSites” of “site A (English)” lists ” site B (English)” and “site C (English)”.
<ul>
<li>Site A (English) => Site B (English), Site C (English)</li>
<li>Site B (Japanese) => Site A (Japanese), Site C (Japanese)</li>
</ul>
And, it provide “Language” column on the Table of Sites in network.
And, it provide “Language Flag” in Admin-Bar.

MSLS Grouping

You can multilingualize by "Multisite Language Switcher" with grouping the sites of the plural same languages.

Kybernetik Services

WPSight

Joe Hana

The WPCasa Polylang add-on is a bridge for the Polylang plugin to make sure all the listing details, rental periods and other text strings of WPCasa are translated correctly.
<blockquote>
Please notice that this plugin is an add-on for <a href="https://wordpress.org/plugins/wpcasa/" rel="ugc">WPCasa</a> and Polylang and will NOT work without the core plugins.
</blockquote>
WPCasa is a WordPress solution that provides an intuitive way to manage property listings and create first-class real estate websites.
<ul>
<li>Website: <a href="https://wpcasa.com" rel="nofollow ugc">wpcasa.com</a></li>
<li>Demo: <a href="https://demo.wpcasa.com" rel="nofollow ugc">demo.wpcasa.com</a></li>
<li>Documentation: <a href="https://docs.wpcasa.com" rel="nofollow ugc">docs.wpcasa.com</a></li>
</ul>
<h3>Languages</h3>
WPCasa Polylang is available in multiple languages maintained by the amazing WordPress community. 
Your language is missing? Please be part of the community and help to translate WPCasa Polylang on <a href="https://translate.wordpress.org/projects/wp-plugins/wpcasa-polylang/" rel="nofollow ugc">GlotPress</a>. Thank you!
<h3>Contributors</h3>
This is a list of contributors to WPCasa Polylang. 
Many thanks to all of them for contributing and making WPCasa Polylang even better.
<a href="https://www.kybernetik-services.com/?utm_source=wordpress_org&utm_medium=plugin&utm_campaign=wpcasa&utm_content=readme" rel="nofollow ugc">Kybernetik Services</a> 
<a href="https://wordpress.org/support/users/joehana/" rel="ugc">Joe Hana</a> 
<a href="https://wordpress.org/support/users/codestylist/" rel="ugc">codestylist</a> 
<a href="https://github.com/sebastienserre" rel="nofollow ugc">sebastienserre</a>

WPCasa Polylang

Add support for Polylang to manage WPCasa property data in multiple languages.

MSLS Grouping vs WPCasa Polylang