It is bound by each Clan's tradition and can be personal to the warrior, look at how it is handled in Blood of Kerensky trilogy. Some of the fluff has noted that the traditional Clans have a strict formula that their warriors do not really deviate from . . . Clans that are a bit more free-wheeling like the Wolves & Sharkfoxes are more likely to vary what gets said when issuing challenges. Anastasia Kerensky in Bonfire of Worlds offers some insights into the Clans' mentality about batchalls- typically it involves a lot of trash talking.
The batchall and bidding between commanders is where the battles start as each side tries to get into the other's head. Natasha messed with Wolf Crusaders, look particularly to how she bid to take Gunzberg- at random removing stars until she had the Crusader at wits' end. What you bid in a batchall can also unnerve the opposition- for instance bidding a secondline force against a frontline can insinuate that you do not respect the opposition, that you do not need your best warriors & material to defeat them.
