A pity… Grav seems to be interesting, but no doc in other lanquage found…
In what language would you need that?
If that holds you back, just try Grav! 
You’d be suprised how much you can do on your own, without having to read the docs even ;)!
if you really need another language try Google Translate
https://translate.google.com/#en/fr/learn.getgrav.org
I just test it English to French it works pretty good
