If you can write your posts in 2 or more(Woo…) languages within one blog, you might want to tell the client browser the language attribute of you posts.
According to <a href="http://www.w3.org/International/tutorials/language-decl/en/all.html" title=" W3C tutorial" rel="nofollow ugc">the tutorial on W3C</a>, language attribute can be declared in the container html tag of your post like this: 
<div id=”post_id” class=”post_entry” lang=”zh-Hant” xml:lang=”zh-Hant” dir=”ttb”>… 
Here “zh-Hans” is the language attribute of your post which means it’s written in Simplified Chinese.
This plugin gives your post a language tag by adding a meta deta to that post.
To add language tag, select it from the language box when you compose/edit a post. Select “None” will delete the language tag.
<h3>Revisions</h3>
2007-12-18, 
0.2: Now you can difine language direction. 
 Insert CSS style into page head automatically to support pretty printing.
 readme file updated for new feature and fixed a error
2007-07-23 
0.1: First release

Multilingual post

This plugin adds a standard compliant language tag to your post and page.

John Clause

Enables <a href="https://wordpress.org/plugins/qtranslate-x/" rel="ugc">qTranslate-X</a> multilingual framework for plugin <a href="https://wordpress.org/plugins/js-composer-qtranslate-x" rel="ugc">WPBakery Visual Composer</a>.
At least version 3.3 of <a href="https://wordpress.org/plugins/qtranslate-x/" rel="ugc">qTranslate-X</a> or <a href="https://github.com/qTranslate-Team/qtranslate-x/archive/3.2.9.9.4.zip" rel="nofollow ugc">alpha pre-release</a> is required.
This plugin is currently a work in progress, please review the <a href="https://wordpress.org/plugins/js-composer-qtranslate-x/other_notes/" rel="ugc">Known Issues</a> and report the features, which did not work for you.
<h3>Known Issues</h3>

WPBakery Visual Composer & qTranslate-X

Enables multilingual framework for plugin "WPBakery Visual Composer".

Multilingual post vs WPBakery Visual Composer & qTranslate-X