Ok the file you want is export_descr_sounds_units_voice.txt.

Open it up and find out what file it sources for the greeks Heavy_1. The vanilla is:
Code:
folder           data/sounds/Voice/Human/Localized/Battle_Map
Greek_Heavy_1_Groups_Created_1.wav
for the first entry and similar ones follow. If its different you need to change all the entries to the vanilla ones.