It is frequently yelled/screamed/shouted/bellowed just prior to smashing into the ground at unholy speeds or as a wild battle cry before plunging head-first into an impossible battle. When combined with a question mark it becomes a question, quite reminiscent of the sounds monkeys make when establishing the well-being of other monkeys. With fewer aaaaaaaaaaaaa's it becomes a less powerful exclamation of adrenaline-fuelled anger/insanity, suitable for minor tasks, such as battles involving units of people at merely platoon level, rather than hordes.
Bajaaaaaaaaaaaa! We go to battle!
Baja? Is there something wrong?
A large Asian person. Will spend most of his time standing in a corner plotting the death of you and your families. Bajaa are dangerous people to be approached at caution. The term is both plural and singular and may be used as an noun or adjective.
shit that guy over there, I think he's Bajaa!