According to some recent import impressions of the newly-remade-for-the-DS Gyakutan Saiban 2 (that's Phoenix Wright 2: Justice For All over here in America), the English translation stored on the Japanese cart seems to be the official translation that will be used here in North America. One of the biggest draws of the game was its extremely well-written and localized script, so many importers were wary that the English option from Japan would be a hack job of pain, suffering, and Engrish.
Worry not! The importer assures us that the writing is as goofy and hilarious as the original, so go ahead and import this sucker, qualm-free. He does mention a few rather glaring typos (which will certainly be fixed before American release), but if you can handle such trivial annoyances, than you can get your gavel on months before the rest.