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.

Are you welcoming visitors from different countries on your site and don’t know how to serve all of them the best possible reading experience? Then just give Lingo a spin and you won’t regret it.
A the best of it: You don’t need to even think about accomplishing this, the plugin does all of that work for you. The only thing you need to do is provide a translated version of each post you would like to show in multiple languages and there you go: Everything works right out of the box. There’s no need for configuring – it just works.
<h4>Functionality</h4>
The plugin provides you with a clean, simple workflow on how to create translations. After you’ve chosen a specific post which you want to translate, you just need to click ‘Translate’ on the post overview. Then Lingo will create a complete copy of the post and assign it a special post type so that it’s completely isolated from normal posts.
After that, you’ll see an edit screen that looks nearly exactly like the one for your original post. You can use the WYSIWYG-Editor, all types of metaboxes and so on. After providing a translation you just need to pick the suitable language and hit ‘Save’.
<blockquote>
Support for <a href="http://www.advancedcustomfields.com" rel="nofollow ugc">Advanced Custom Fields</a> will soon be added.
</blockquote>
<h4>Supported Languages</h4>
Lingo currently makes use of all languages that are available on the ‘Site Language’ select-field in the admin area of your site (‘Settings’ > ‘General’ > ‘Site Language’ ). But don’t get me wrong: It doesn’t matter how many languages are installed on your site, Lingo works with all of them anyway.

Lingo

Show customized translations of your posts or pages for visitors from other nations.

MSLS Grouping vs Lingo