You need to have a Qt translation for your new language,
otherwise your language won't be loaded at runtime.

To add a new language:
1) Run 'cd src/sdk' (change to the parent directory of this file)
2) Run 'make ts-untranslated'
3) Rename translations/untranslated.ts to translations/<lang>.ts
4) Run 'make qmake'
5) Do your translation. Just run 'make' whenever you want to test it.
6) Run 'make commit-ts'
7) Submit the translation for review

To update an existing translation, just run 'make ts-<lang>' instead
of steps 2) to 4).

More information is available at https://wiki.qt.io/Qt_Localization -
these instructions apply here equally, except for the different
directory names.