It's possible that they stored some sound effects in a single file, perhaps an archive of some sort that gets extracted at runtime. There are a lot of files under the SoA sound folder (like hundreds), but none of them are helpfully named, have you checked all of them? What kind of tool are you using to actually play these files?
Probably not entirely helpful, but keep in mind that this game's audio was compressed to fit onto a single GC disc instead of 2 DC discs. Maybe investigating the DC version would yield some results.
Probably not entirely helpful, but keep in mind that this game's audio was compressed to fit onto a single GC disc instead of 2 DC discs. Maybe investigating the DC version would yield some results.