I haven't messed around with the japanese version yet, though being curious I sent Mobage an email asking if they had plans to localize Nanoha, though their reply was generic as expected but they did give me their feedback site address and I started a suggestion their to localize the game in english.
http://feedback.mobage.com/forums/19...3847841-nanoha
If you would also like to see them localize the game for us drop a vote!