A user on a Reddit thread about challenging JRPGs summed up the feelings of many when they said:

Always inherit: (Tarukaja, Rakunda, etc.) — they stack up to ±3.

The UNDUB edition of Shin Megami Tensei IV: Apocalypse is a special version of the game that features a number of changes and improvements over the original release. Some of the key features of the UNDUB edition include:

Playing the UNDUB version of SMT4A on a 3DS requires specific technical steps, as Nintendo did not officially support dual-audio tracks in this title.

The iconic battle mechanics reward you with extra actions when exploiting enemy elemental weaknesses, but penalize you heavily if you miss or hit a resistance.

For the dedicated JRPG fan, the Shin Megami Tensei IV: Apocalypse -UNDUB- on 3DS is not just a patch; it's the definitive edition of a modern classic, and a powerful testament to what fan communities can achieve when they take preservation and customization into their own hands.

I'll cite the relevant sources: Wikipedia for game info, GBAtemp for the patch and review, Nintendo Life and Destructoid for reviews, and the Megaten Wiki for series context. I'll also cite the LumaCFW guide and the 3DS hacking community resources.

Players use a custom patch folder that intercepts the game's file requests. When the system boots the English version of the game, LayeredFS replaces the English audio files with the Japanese voice archives on the fly.

Double-check the following: ensure the "luma" folder is in the root of your SD card, verify the Title ID folder is correct for your game's region (USA vs. EUR), and confirm that "Enable game patching" is turned on in your Luma3DS configuration menu.