when you are going to start a new translation, please make sure that there is no existing contribution in the database. When there is already one, which is up-to-date, please contact to author and offer your help. Feel free to ask me, when you are in doubt.
When you translate a new language pack, please make sure your translation follows this actual guidelines:
https://github.com/phpbb/phpbb-translat ... delines.md
Please see also the guidelines how new translations will be validated:
https://github.com/phpbb/phpbb-translat ... idation.md
Please read this topic and learn how to create the ISO-tag for your languages: viewtopic.php?f=491&t=2393036
If you have any questions, please feel free to ask me.