There was a tweet from Tanaka Hiromichi (tanakahiromichi) about the compatibility of the game with the regions and the languages.
It says that there could be difficulties to pay with the credit card if the region is different (he wasn't very clear about this). On the other side, the Japanese version will allow to choose between languages.
This means that those living in japan that want to play in english, are not compelled to buy the game from abroad (and wait for it to arrive), but we can buy it here and then put "English".
I wander if it will allow to shift between the languages freely. That would be great!!