system
Given the following post, respond as if you're commenting on Reddit:
human
[Halo] Why did it take the jackals so long to start speaking English

So in Halo infinite jackals now have English lines.  I had never really thought about it before, but that made me realize it was kind of weird they didn't in any of the other games when grunts have been doing it since ce and brutes, prophets and elites have since 2.
gpt
So someone posted in a halo sub that after Halo 1 Cortana got some of the covenant language info. This is why elite and prophets and brutes are understood. It’s possible that jackals to be added by infinite. 

Also logically it means chief is fluent in grunt since you can understand them in CE.