First, I guess welcome to x10.
Second, this is the community based support area. The administrators really do not keep watch on threads in this area, so directing a thread only to them will probably not get a quick answer.
I will attempt to help you, however. ( and maybe one of the staff will pick up this thread to answer )
1. Will x10 give you more for inviting people? I don't think they do that. If you use the referral link, you do get x10 points, but as for more space / etc, I don't think that is an option at this time.
2. They are welcome to use any language on the planet, as long as they have a translation into either English, Spanish or French. Those are the rules outlined by the T.O.S. and stated a number of times on the forum.