A really simple to use plugin which provides support for additional languages for your pages and posts. Does not work with custom post types and some themes.
Adds title and content edit boxes for each additional language on edit pages for posts and pages. Translation indicator available for post list on admin panel (can be turned off).
Includes widget and shortcode to generate language selection.
When a language is selected, displays all pages, posts and menus based on selected language. Different actions for untranslated content available in the settings.

A Simple Multilanguage Plugin

Multilanguage support for pages and posts. Displays content based on selected language. Includes widget and shortcode for language selection.

Fahad Alduraibi

Do you write posts in different languages? 
Would you like your blog theme language to be the same as the language in which your wrote your post or page?
With this plugin you can set the language of your blog per post and also per page, that is if your blog is in English and you wrote a post or a page in Spanish or Arabic you can set the language of your blog to match that post’s or page’s language, so when your visitors open that post or page they will see your blog in that language. You don’t have to translate your theme and plugins if they come with translations and even it will change the direction of the view to RTL (Right-to-Left) if your language is RTL based.
<ul>
<li>The plugin does not provide any translations, it only changes the themes and plugins translation language if they provide there own translations. </li>
<li>The available languages are only the languages that WordPress already recognizes and supports.</li>
<li>The plugin only works for posts and pages, the front page will show in the blog default language.</li>
</ul>

Per Post Language

This plugin does a great job when all you want is to have a page in a different language. Since it changes the WordPress locale, it affects the HTML language attributes, the language attributes, generated by SEO/OpenGraph/sharing plugins, etc. which is great.

I was just researching the proper action hook to use to switch the locale per post or page, when I found out it has been already done and packaged in plugin. It saved me an hour or two developing my own solution.

Does just what it says

This plugin allows the user to set the blog language per post or page while having a default blog language.

A Simple Multilanguage Plugin vs Per Post Language