To deal with managing the various translations/localizations of Beats, I have uploaded the strings to crowdin, a collaborative translation tool that supports Android.
If you are interested in helping out with the translations, please visit that site and start translating! In particular, I am strongly looking for someone to help out with Japanese translations. Once translations are complete, I will release a quick Beats 1.5.5b update which will include some of the updates on the Changelog page (particularly a setting allowing you to explicitly change the game language).
As always, make sure to join the Google group to keep up with updates. Happy translating (and happy Easter to those who celebrate it)!
BeatsPortable Forums: http://beatsportable.com/forum/viewtopic.php?f=4&t=1011