ROM Hack I want to undub Tales of Phantasia

[Alchemilla]

I heard how to undub ds games but how do I undub gba games? As much as I enjoy hearing that guy say ENDEGNEIGHSHYON I kinda want to get rid of it and use the Japan voices instead.

 

[FAST6191]

Much like the DS has the SDAT sound format the GBA has its own format that usually gets known by things like sappy, it is perhaps not as ubiquitous as SDAT but I can safely call it the dominant format. It is fairly well hacked/understood, however with the GBA not having a filesystem you get to do manual injection, or worse, for each file and that gets to be quite annoying (quite doable though). http://www.romhacking.net/documents/462/ has a nice technical overview, I have seen good (ish) guides and tools come out of Fire Emblem, Golden Sun and Advance Wars.
http://www.feshrine.net/hacking/Fire Emblem Music Hacking Tutorial.pdf (warning PDF)
http://forum.goldensunhacking.net/index.php?topic=250.0
http://forums.warsworldnews.com/viewtopic.php?t=2002

I have a tiny bit in my hacking docs on the DS but it was one of the sections I skimmed over to go back to later.

If the game does not use sappy sound format or another known format (there were a few other tracker/sequenced formats available for commercial GBA programmers) then you get to read up on the GBA sound systems and have fun with that http://belogic.com/gba/index.php

 

[Alchemilla]

Man I don't even know how to open up a ROM or anything and I'm not the best at ROM shit, so all the explanations need to be for five year olds.

Edit: I've never tried GBA ROM shit. Just DS ROM shit. It didn't work out.