More and more often, I have to install WordPress in several languages. There were basically two solutions for creating websites in more than one language on WordPress:
either install WordPress for every wanted language,
or use one of the plugins available for multilingual blogs, like WPLM for instance.
When WordPress 3.0 was issued, including the multisite feature (allowing the creation of several blogs within one single WordPress installation), I then indicated that the time had come to offer a third solution – solution which still today, seems the most valid to me. In reality, the only thing that was missing then was the possibility of managing the relationships between posts and their translations.
However, it was for me the right time to work more intensively on the third solution and to create the Multisite Language Switcher plugin.