Translations are handled online via the Transifex website: https://www.transifex.com/projects/p/mayan-edms/. To create a translation team for a new language or contribute to an already existing language translation, create a Transifex account and contact the team coordinator of the respective language in which you are interested.
Feel free to open translation issues inside Transifex itself if you have a question about the usage or meaning of a source text string. If you open a translation issue, it will be your responsibility to close it after you get an answers that satisfies your question. Administrator will not close new issues as they have no way to determine if your question has been properly answered. However to avoid clutter, answered questions will be scanned periodically and closed if no activity is observed from the original poster in a period of time.