This extensions provides automatic language detection support for Neos. Currenty, the detection gets only triggered if there is no language segment present in the url (e.g on the homepage or when obsolete links are called).
If you already have a multilanguage site, you have nothing more to do. Otherwise follow this tutorial to translate your content: http://neos.readthedocs.org/en/1.2/IntegratorsCookbook/TranslatingContent.html