Jaffa could covertly communicate with each other.
"Batu" had originally been implemented by the Goa'uld System Lord Hera as a ‘battle language’ for her Jaffa that could be used for secret communication during combat.
Orders could be yelled out in the heat of battle and the enemy would be unaware of what was being said. It had proved so useful that several other System Lords sought out the language and taught it to their own Jaffa…thus ending Hera’s advantage.