EDIT: If you want to manually create this modifiication, then follow these steps:
1) Download ficedula's Cosmo and ficedula.dll...all can be found on the program compilation sticky. Set them up correctly.
2) Open Cosmo. Let it make it's index, and whatnot. Afterwards, if you get a dialog box, click "Tools," "Internal Editor," and skip to step four.
3) If you don't get a dialog box, report it back here.
4) Proper spell names...now, of course, you can edit them to however you please, but this is as best as it gets for modernization, if you ask me:
Fire - Fire, Fira, Firaga
Ice - Blizzard, Blizzara, Blizzaga
Lightning - Thunder, Thundara, Thundaga
Earth - Tremor, Quake, Earthquake (Quakera and Quakega didn't sound cool enough)
Restore/Full Cure - Cure, Cura, Curaga, Full Cure
Revive - Life, Full Life
Gravity - Gravity, Gravira, Graviga (derived from Kingdom Hearts)
Poison - Bio, Biora, Bioga (made these ones up...)
Mystify - Confuse, Berserk
Seal - Silence, Sleep
Exit - Exit, Remove (I think Remove is here...)
Barrier - Barrier, Magic Barrier, Reflect, Wall
Comet - Comet, Meteo
Time - Haste, Slow, Stop
Destruct - DeBarrier, Dispel, Death
Contain - Freeze, Break, Tornado, Flare
Shield and Ultima remain the same...