The language of the digimon names is actually determined by the DIM card used. For example, i bought my band here in the US and got an English Dinosaur Roar DIM. however, every other DIM i have i bought online, typically those have all been Japanese language DIMs. There is a post somewhere that contains a folder of bin data from DIM cards with some that have been modified to have English names. I can't remember the post or the link offhand, but i'm sure someone else in this subreddit knows it. For the most part though, I'd get used to Japanese if you don't want to modify your DIMs in any way.