I have the same problem with the Spanish translation. I have been looking at the messages.po file in the Spanish translation and is very old and it is incomplete. How can I translate the whole site. I am willing to do the job and share it with the community but I need to now how to compile and install a language pack. I follow the instruction in your TRANSLATE.md with no positive results.
Have you found the correct translation? Or have you completed the missing parts? I´m from Brasil too, and I´d like to get the complete translation. Could you share it with me? May I help you with something?