As the subject line reads, I stumbled across a thread in the Official PSU forums with a link on how to add the Japanese voices of AoI to the US version. Sadly this is only for PC users and its reported in the updates given on the thread that certain voices don't work. However, they are working on it to make sure how to get it properly working.
For more information on this check it out for yourself.
Japanese PSU:AoI voices
For more information on this check it out for yourself.
Japanese PSU:AoI voices
