Yes, the most languages exist unfortunately only partially. So you definitely need to review all sentences because they're probably outdated or completely false.
If you have any question about translation, in example for a string or something, don't hesitate to ask. :-) We're trying out Transifex at the moment. On Transifex, you can see any progress of translations, create issues or start discussions for questions, bugs, fails or anything else. :-)
The translation process is also extremely simple, so you won't need a long time to work in.
I've invited you into our Transifex group, check your mails ;-)
Thank you in advance for contributing!
my demo will be ready in a 3-4 days i guess, it will be great to even test user load :D
Sounds nice! I also have a small performance tip for you, because I don't know how big your database will be, how fast you internet connection is and so on. On my side the module
"Page_Speed" has drastically increased the performance of Ampache on Apache2.4. It's maybe worth to test it also on your side ;-)