I got 3 year old African grey parrot 6 days ago. I was told (no proof, just sellers word) that it spoke human words in previous home. First day it was quiet. After that it seems to be well adjusting to new home and takes seeds from my hand and makes a lot of 'natural' vocalizations/whistles but not a single 'non parrot' sound. Is this normal at this stage? Or was I lied to about it previously mimicking human speech? I mean does it make sense that the new home caused it to stop all 'mimicking' and human speech, but continue to make 'parrot sounds and whistles and vocalizations?