When reading your twitter posting at https://twitter.com/graphhopper/status/752448767580860417
Is translation done so far by single pull requests on github?
Has there ever been an evaluation to support language translations by any online service like https://weblate.org or Transifex?
Weblate is the smaller one, but it is developed by an enthusiastic opensource programmer, see http://blog.cihar.com
One OSM related project hosted at weblate.org is Osmand.
Weblate can be used on the central server, see https://hosted.weblate.org …or create a Weblate instance on your own server.