My DSi is Jap ver. and I use AK2 to archieve Yugioh WC 2009.Although the game 's version is (U) 3833(I just can't remember the code), when I play, its language is Japanese
Well you can try the Japanese version if you like because it's actually in English, the description, options and etc are all in English.
That's the annoying thing about the dsi-it's preset, I believe the dsi itself requires hacking... If you had a plain ds/dslite, it would have been rectified the moment you started, prehaps someone here can help... (never import region locked consoles unless you can understand other laguages )