Well this is kind of a nice surprise. Although perfectly playable in its original Japanese format, it appears that a fan translation group has released a patch translating all of the text and lyrics to the Rhythm Tengoku, Nintendo’s late GBA entry that served as the precursor to the Rhythm Heaven games that actually made it across the pond. Best experienced with the Game Boy Micro hardware it almost launched with, the series has been fairly consistent across the years but I consider this first game as the best.
Romhacking.net has the patch hosted, if you know what you’re getting into, although I’m still debating whether or not to replay the game in English myself. There’s something inherently… wrong in seeing “Don-don-pan-pan” translated in a more-discernible language. Half of the game’s charm for me came from not being able to understand Japanese at all; and as I learned a little bit of the language later on in life, appreciating the subtle puns and onomatopoeia of the game’s lyrics. Even Treehouse’s best efforts to carry those over in the later English releases have fallen flat for me, personally.