As you already know Stern it actually works well on the servers between other players!
Word of warning though, it does replace the original sounds (also in single player), if possible it would be preferable to add sounds and keep the originals. Also because players who don't have the modded files could give an original command causing perhaps confusion (a silent "follow me" would become "in my line of fire" for a player using the modded files and so on, at least I assume it would work that way).
So maybe for now players should make a backup of the original files.
I have looked through some SP commands and not too many seem very useful (most are in MP anyway) although those under 03 and 06 have some actions that could be used like destroy, silent kill, heal and so on.
But there are some lines in SP that could be fun to be able to use like "that was close!" or "under fire". (of course won't help with our no spam policy
)
Edit: will this also work for players using a different language than English or would that need a modification per language?
Great job man!