Isidore, Etymologies 12.7.24
psittacus Indiae litoribus gignitur, colore viridi, torque puniceo, grandi lingua et ceteris avibus latiore. unde et articulata verba exprimit, ita ut si eam non videris, hominem loqui putes. ex natura autem salutat dicens ‘have’ vel ‘chaire’. cetera nomina institutione discit.
The parrot comes from the coastal regions of India; it is green in colour, with a purple collar and a strong tongue that is more copious than that of other birds. So it even produces articulate words, in such a way that if you had not seen it you would think it was a human speaking. It is in its nature to greet you, saying ‘Hello!’ or [in Greek] ‘Good health!’. It learns other words by being taught them.
For more on Isidore and a couple of nice images, see here.