For years, there has only been one option if you wanted to build a multilingual Joomla site.
Joom!fish is one of the most popular and widely-used extensions in the Joomlasphere and has a great team behind it, including Joomla core team members Alex Kempkens and Robin Muilwijk. Its recently been updated to work on Joomla 1.5.
However, there will soon be an alternative option available. Johan Janssens is close to releasing a new translation component called Nooku. You can see from the screenshots that it will have a strong graphical interface and may be easier to use than Joom!fish. Rather than heading over to the Joom!fish component you’ll be able to change languages from within each content item.
Its development is being partly funded by a number of European companies and organizations, amongst them the Belgian police. There’s a teaser website at http://nooku.org where you can register for future updates and Johan’s blog is Joomlatools.org.
One of Joomla’s main strengths has always been its popularity with users in many different languages. Joomla 1.5 has already moved to UTF-8 which allows nearly all languages to be shown within a single encoding setup (no more messing around with encoding settings). And now with two strong multi-languages alternatives available for 1.5, Joomla is likely to continue its dominance as the international CMS.