Thanks Wraith.
I live in Japan and based on whether there is an official Japanese release of a game, the activity of servers completely changes. Only the really hardcoe buy English-only PC games.
A Japanese PC version typically comes either subtitled or dubbed and in native-language packaging.
To be honest I am not sure which SD would do.
My advice would be to go here: http://www.splashdamage.com/forums/forumdisplay.php?f=17
The devs are much more active on their forum and hopefully one of them can answer. Cheers.