system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can parrots imitate human speech, but our closest relatives, chimpanzees and gorillas, cannot?
gpt
Primates have vocal cords which are used to make sound, then your mouth and tongue to form that sound (humming) into more distinct sounds used for words.  Human vocal chords and tongues have evolved in a way that makes them precisely controllable (which is needed for speech), while our close relatives do not have this adaption, so are only capable of making barks and yelps.  

Birds make sound through a completely different method.  Instead of using vocal chords, lips, and tongues, they have a syrinx, which are almost like speakers.  They just control the vibration of the syrinx very precisely, so they can imitate humans, animals, and even machines.  Many birds don't have particularly sophisticated syrinx, so they can only squawk and chirp, but some birds have evolved the precise control needed to emulate almost any noise they hear.