Right, i'm back once again, with some codes for PAL Yoshi's Story that i made sometime ago...
Pitch Modifier(ConkerGuru)
8100CFA6 ????
Default value=3F80
SFX & Music is heard as bleeps and bloops(ConkerGuru)
8100EC60 2004
8100EC62 0000
8100EC68 2005
8100EC6A 0014
8100EC6C 2004
8100EC6E 0082
Make sure you turn on the code before booting up the game (assuming you're using emulator). If the game is already running, reset the game, or reload a savestate(the latter method may not work in every single state save though, so don't expect this to always work. For the ones that do work, well, good luck..)
Yoshi Speed Modifier(ConkerGuru)
8102337E ????
Default value=3F80
screen boundary area modifier??(ConkerGuru)
8102A0E6 ????
Default value=3F80