how do you expect it to be language for all, when the samp client is in English? Last time I checked that's the only language for the program.. (Correct me if I'm wrong.)
It's really simple, majority of people will learn English not just to play on some samp server, but for life in general, because it's the 3rd most spoken language in the world.
The server is based in the UK in which case, the main talk will be English. There is a reason why there is a non English filter in the server.
Besides there are all types of moderators and admins on the server which can provide the language that is needed if there is some type of barrier between the player and admin.
I could be wrong in all this but that's the way I'm seeing it.