Battle language refers to any formalised method of communication used specifically for military purposes.

Some peoples during the days of the Faufreluches maintained their own battle language, including some Great Houses such as House Atreides, House Harkonnen, and the Bene Gesserit.

The idea behind a battle language was that communications could not be intercepted by enemies, and that it could be easily recognised and not mistaken for anything else in the fog of war. It usually consisted of hand signals, or, in the case of the Bene Gesserit, an ancient language long since forgotten by any living peoples. This language would often be drawn from Other Memory.