Hi, and thank you for your interest!
YunoHost is being translated using Weblate, a web tool designed to ease translating for both developers and translators.
Translation project for YunoHost into Greek currently contains 1544 strings for translation and is 14.4% complete.
If you would like to contribute to translation of YunoHost, you need to register on this server.
Once you have activated your account just proceed to the translation section.