I guess there will be a Finnish translation too(giving the number of talented Finnish members of the community).
Actually, I seriously doubt that prospect for a couple of reasons:
Finnish people know English very well and are conditioned to at least listen to it in most TV and movies, they are all subtitled to Finnish... and we actually study it in school longer than Swedish (or Finnish, whichever happens to be the second domestic language). Games, though - if not meant for wide audience including children - are very rarely translated to Finnish, which means there is rather limited gaming (and actually computer in general) terminology in Finnish, most terms are anglicisms or loan words from English. Moreover, Finnish terms usually sound plain dumb or clumsy... So English is the expected norm that most Finnish people expect and accept in games. Also the limited vocabulary means that it would be very difficult to translate FreeSpace related things to Finnish in a way that wouldn't be completely laughable.
Besides, with the Finnish language it would be more than likely that at some point you would run out of character room on HUD or interface while struggling with overly long words...
Also, to my knowledge there hasn't been any intention to do this in past years to translate anything FreeSpace to Finnish, and there has been a lot of Finnish fans around for a long time. I'll take my hat off if someone actually manages to make a credible Finnish translation of FS2/any total conversion, but I don't really see that happening, either motive-wise or even possibility-wise. And call me old-fashioned, but we might be better off without one... "aliavaruuskäytävä" sounds more like an underpass to go under the space, rather than "subspace corridor", and although there would be much hilarity in translating a lot of the comm messages to Finnish, I think it would only have novel value for most Finnish players and then they would switch back to English version (kinda like I did with GIMP, the Finnish translation was just messing things up for me...).
Personally I think that the only motive for translating the game to Finnish would be if someone made a Star Wreck mod of TBP.
That could definitely not be left in English, not at all...