The Community Translation Team is responsible for the localisation needed within The Joomla! Project, for sites, announcements, marketing, official extensions etc. You can find all the localised Joomla's Projects here and follow the team on Twitter.
You can also join the Community Translation Team on the dedicated room on Glip.
Please check the Core Translation Team to get involved with the translation of the Joomla! CMS itself.
Read more: Community Translation Team