Opportunity: Phabricator is ready to be localized.
Problem: it comes without any translations.
Requirement: Wikimedia needs at least the strings visible to users of a bare bones Phabricator instance with Legalpad.
Possibility: create a Phabricator project at http://translatewiki.net and let our community contribute some translations. If there are translations available somewhere, they could be integrated as well. At some point Phabricator could get the fresh translations directly merged to your code base, just like we do with MediaWiki (probably the most localized piece of software in the World).
I will try to find volunteers to help setting up the project. In the meantime, see https://translatewiki.net/wiki/Translating:New_project
Twin report: https://phabricator.wikimedia.org/T225