It would be a pleasure for me to do that. I like translating.
This guide i did was just a bunch of relevant information i thought would be useful to know for anyone thinking about buying Screeps, and also for anyone wondering how to play. However, to do a proper "official" guide i should be given a bunch of texts to translate.
A good idea would be to also translate the official docs web, which is a lot of stuff but still it'd be a pleasure.
Count on me if you devs want to do it.