WordPress Plugin qTranslate X Description:
The plugin offers a way to maintain dynamic multilingual content on a WordPress site. While static localization is already excellently implemented and offered by WordPress framework through po/mo file framework, it is still impossible to maintain dynamic multilingual content without an additional specialized plugin, a kind of which qTranslate-X belongs to. For example, what if you need to make title, content and excerpt of a page to be multilingual? In theory, it could be handled by po/mo files, but in an insanely inconvenient way.
Related to WordPress Plugin qTranslate X
WPSlug.com data has a list of 843 WordPress CMS installations Using the WordPress Plugin qTranslate X.