Can you play American games on an Japanese psp?

Answer 1

Yes but if there is a game for Japaneses and English you can save Japaneses games with Englishes data,all PSP can play PSP game Englishes or Japanese.
PSP games are region free, any PSP game will work on any PSP.

Answer 2

Yes they say it does play American UMD games but not UMD videos. Here is alink to a recent question of the sort.

Can_you_play_Japanese_games_on_an_American_Psp

Your Welcome. -German American Dude