Explanation: Julius Caesar, in the course of his civil war over the leadership of the Roman Republic, pursued his longtime ally-turned-enemy Pompey Magnus to Egypt. Egypt, which was aligned with Rome, thought they would get in on the likely-looking victor's good side by handing over Pompey to Caesar.
Caesar had a standing policy of offering his enemies in the civil war unconditional mercy after defeating them, to emphasis his argument (true or false) that he was not a tyrant nor seeking to overturn the Republic. The Romans, in general, frowned on foreigners meting out ANY sort of justice to Roman citizens - much less Roman officials! And Pompey and Caesar had a long history together, having known each other fairly well for some ~20 years at that point, and having worked extremely closely for ~15 years of that. Caesar may even have still considered Pompey a friend.
... so in context, Caesar was deeply angry when the Egyptian court presented Caesar with Pompey's head, sans body. Not a smart move. HE WAS A CONSUL OF ROME!
It's often joked that sounds of other languages which have no close equivalent in one's own language often sounds like onomatopoeia instead of words. Here, Caesar is just practicing to communicate with the Batavian auxiliaries, he didn't mean to tell the Egyptians to cut Pompey's throat!