The Wikimedia foundation sponsored the development of modular translation layer which allows the translation strings to be imported from a separate repository. Translations exist for several languages that are not in the core phabricator code base and work continues on translatewiki.net to improve the quality and completeness of the translations.
The output gets integrated into the repo at https://phabricator.wikimedia.org/source/phabricator-translations/ by a combination of automated commits from translatewiki and a manual compile step which I run occasionally as part of code deployments.
It would probably be valuable to include some of these translations with phorge or and least to include documentation about how to install them.