I wrote a little tool that helps you when translating Raddit into your own language.
It works by comparing the current English translation file, which is maintained by u/emma, to the name of the file you provide. All the text that has not been translated yet, is then shown.
Overview of existing translations https://gitlab.com/edgyemma/raddit-app/tree/master/src/AppBundle/Resources/translations
If a file for your language is not there yet, copy the file for English, translate it and create a Merge Request on GitLab (search online for a how-to if you don't know how)
I hope this can help you :)