The kit requires additional tools in order to properly extract strings from the source code. You'll need to run this once locally:
# pkg install gettext-tools p5-Locale-Maketext-Lexicon python27
Regenerate source strings that can't be found in the template generation step (XML contents, etc.):
# make src
Regenerate the translation template using:
# make template
Merge the latest template changes into the actual translations:
# make merge
Remove the compiled translation files from the system/chroot:
# make clean
The build system will automatically pick up all registered languages.