I don't know if this is a stupid question or not since it hasn't been posted on the forums: Is there a way you can change the sounds that the units make.
Take a look into the sound.txt in the ..\CTP2_data\default\gamdata folder. This file give an certin unit sound its according *.wav file. The sounds themselves are defined in unit.txt. The *.wav fieles themselves are located in the sound.zfs in the ..\CTP2_data\default\ folder you need a program called unzfs.exe to unzfs the *.zfs file. Search for it in the web. If you need more pieces of information about it please post here.