Weblate – one of the most popular web translation management system – provided Unity with a free hosting plan. Thanks to it we can now open translation effort for all interested people. If you want to contribute simply go to:

https://hosted.weblate.org/projects/unity-idm/

and start translating. Note that if you want to start a translation to a new language, then please let us know via mailing list: we need to enable the new locale support, what is a tiny but required work.