Multilanguage

1. In 1.7.1 was introduced the new Multilanguage Status Module:http://community.joomla.org/blogs/community/1501-171-new-multilanguage-status-module.html
In 1.7.3, a necessary improvement is implemented: checking the status of the Contacts linked to an Author, as it is necessary to create a unique contact per author and tagged to 'All' languages OR one contact per published Content Language.
If an error occurs, a message is added in the modal with the user name concerned (Thanks Marc Studer and Christophe Demko): 

2. It is now possible to customize the Site Name depending on the Content Language displayed.
A new parameter has been created in Extensions=>Language Manager=>Content tab=>Edit a Content Language:

3. By enabling a parameter when editing the Language filter plugin, users will at last get a new feature that has been expected for long:
the Content Language prefix will not be used anymore in the url for the Site default language when SEF is on!

Front-end result:

4. The batch processing in various Managers in back-end now includes a Language field.
It is now possible to batch-change language for ticked items, as well as batch-copy including Language change to another Menu (in Menu Manager) or another Category 

Source: Joomla.org