system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: How do parrots copy humans on what they say, how does that work?
gpt
So the short answer (being "how") is actually relatively simple; their tongues are so large and complex that they can use them to produce exceptionally distinct sound waves, reproducing not only human speech patterns, but the patterns of animals. Hell, any sound really, as there's been cases of domesticated parrots mimicking household appliances.   


As to "why," the answer gets a bit more complicated. What's known for certain, and this is true with many species of avians, is that they have to learn or adjust to the 'local' mating call to find a mate. Imagine, if you would, you travel to a new country and now have to mimic their accent to even be seen as a viable mate, or even human. Weird, but that's how birds work particularly when their mating calls are from a distance. 

Aspects of mimicry outside of mating are a bit theoretical, as it can be assumed to be bonding/play, or simple attempts at communication. 

Hope that helped.