In the 1.7 release of Joomla! was introduced a cool functionnality, Menu Items Associations for a Multilanguage site.
See: https://community.joomla.org/blogs/community/1468-multilang-in-17-whats-new.html
It's a pleasure to announce here that Joomla 3.0.2 is bringing an improvement we have all been waiting for:
Items Associations
It is limited in 3.0.2...
In the 1.7 release of Joomla! was introduced a cool functionnality, Menu Items Associations for a Multilanguage site.
See: https://community.joomla.org/blogs/community/1468-multilang-in-17-whats-new.html
It's a pleasure to announce here that Joomla 3.0.2 is bringing an improvement we have all been waiting for:
Items Associations
It is limited in 3.0.2 to the articles and article categories, but will be for sure extended to all core components (if someone codes it... 
at Benjamin).
Compatibility with 2.5
The new feature is backward compatible. One just needs to save again the parameters in the System Language Filter plugin and make sure all is fine for the already associated Menu Items.
The screenshots below are done from an updated Multilanguage demo site ( See 2.5 version here: https://multilingual-joomla-demo.cloudaccess.net/ )
How does it work?
1. Edit the System Language Filter plugin and make sure that Items associations is set to Yes
2. Associating Articles Categories
When the parameter is set in the plugin, a new Associations tab displays when editing a category. All Content Languages display and a dropdown lets you choose for each of them among the categories set to that language.
3. For the categories for which association is implemented (Articles Categories for now), a new Association column will display in the Category Manager. Hovering the icon will display, as for Associated Menu Items, the associations implemented.
4. Associating Articles
A new Associations tab displays when editing an article. Clicking on the Select button will open a modal with all filters where one can choose an associated article in another content language.
5. A new Association column will display in the Article Manager. Hovering the icon will display the associations implemented for a specific article.
6. The interface is similar for menu items associations.
7. On the front-end, here is a page displaying a list menu item of a category set to en-GB. We have no menu items set to display the articles, but some articles are associated (the "Introduction" article shown above).
8. Let's click on the "Introduction" article
9. Then click on the French flag in the Language Switcher module. The associated article will display.
10. That's it! The behavior is similar for categories and menu items.
Who did it ?
We have here to thank Benjamin Trenkle who proposed code for this new feature in the feature tracker.
He is a freelancer and uses joomla most of the time for creating extensions and some templates for his customers.
He also created a club management component for joomla!
His site: https://www.wicked-chick.de/
Read more https://community.joomla.org/blogs/community/1695-multilanguage-in-302-whats-new.html
