I'm translating YaCy to Portuguese (pt) and it's harder then it should be.
I've already made translations for other software, namely Manjaro Linux components (Octopi, pacman, etc) and it's much easier
The use of .po language files instead of .lng makes a great difference, namely because if you use a site like Transifex a large number
of users can co-operate in the translation of the same file.
In the current situation no one is aware of what others are doing. Do you know how many of us are trying at the same time to
translate the .lng file into the same language?
I may be translating something that was already translated by someone else and that's a waste of time for all involved.
Transifex is a great solution because each language may be assigned to a mantainer and as many translators as necessary and
all in a coherent way.
YaCy being a Web search engine makes all sense to translate it into every possible language and in my humble opinion as fast
as possible so users have another alternative to Google (I use Duck Duck Go).
I don't know if it's possible to use ,po files with your code but it would be great if you could follow that approach.
I bet you would be astonished how fast YaCy would be translated to every available language worldwide.
I thank the developers for sharing with us all the result of their effort and hard work.
PS - I suggested .po because I can't find .lng in the list of formats supported by Transifex http://docs.transifex.com/developer/formats/
There is also an opensource and free (projects must pay Transifex, it's free only for translators) alternative that seems very promising http://zanata.org/