Parrots are able to mimic human speech due to their unique vocal anatomy, which includes a syrinx, a vocal organ located at the base of the trachea. This allows them to produce a wide range of sounds and mimicry. Additionally, parrots are highly social animals and are known to mimic sounds they hear in their environment as a way to communicate and bond with their human companions. With practice and exposure to human speech patterns, parrots can learn to imitate words and phrases accurately.