OK I have been having a play with this language setup and there are a couple of solutions in the form of Joomla plugins.
1)
http://extensions.jo...content/1767/detailsI have tried this one and it is dead easy to use. You install the plugin and then place a small token
{joslang_select} somewhere where a language drop down menu can appear (you may need to edit the template source code or place it in a block somewhere - you can even include it in the text of relevant articles which have translations). In the plugin settings you can specify up to 7 languages (eg. just put a simple list like:
en=English
fr=French
in the plugin settings box. Then use your two letter code to tag content when writing pages etc. for the website - eg.
[en]Hello[/en][fr]Bonjour[/fr]
When you select a language from the drop down menu only the content tagged with that language will be displayed. I haven't tried it but I guess you can also use it in menus and block titles etc. too.
2)
http://extensions.jo...content/6348/detailsI haven't tried this one yet but it looks as though it can all be automated by the user selecting their own language and then only content in that language will be displayed. Sounds neater but if I understand correctly you effectively produce two documents for each article (each tagged with its own language).
The first approach is more flexible - you set up your site as you want and then can translate what you want when you want and add tags. No tags and it displays in the default language - tags and you get what you want. It also has the benefit that you only create one document for each article (rather than the second method where I think you have to produce 1 document for each langiage for each article. This method is more transparent but then you only get content in the language you choose. add to that it digs into and modifies a lot more native code and you would be relying on the developers to keep it going through new versons of Joomla. The current version has been tested to version 1.5.8 but already Joomla is on 1.5.10 and the updates are security fixes you want to apply - whether you language extension would then work is a bit 'suck it and see'.
There is also an automatic translation extension (joomFish) which a lot of people use. I am not a fan of automatic translation but it is there as an option.
With respect to 'native' language packs for Joomla - I have tried the French pack alongside the English pack and it is simple to choose the default language for the site (a couple of clicks). This translates the backend as well as obvious bits in the front end (and yes the dates are updated automatically to reflect the current language). When a user registers you can give them the option of updating their profile which means they can specify their own native language.
It would be very neat if option 1 above (josLang) could be enhanced one step further by reading the users own language preference rather than having to manually select the language from a drop down (although this is a nice option for unregistered visitors).