i did eventually figure this out.
i extracted the romfs folder of an English CIA file of SMT IV and was able to get the Japanese cartridge translated using Luma's LayeredFS.
i'm expecting a few Japanese 3DS game cartridges for some games i have installed on my system in English. i have another 3DS system i would like to play these games on, hence the need for the cartridges to carry over my progress.
i was wondering if it would be possible to extract the English...
Is it piracy if it was released for free? Not in my opinion, but I also think it's not piracy if buying it isn't owning it, and it's not piracy if you can't buy it from the original creators anymore.