Many species can imitate human speech or other sounds, and the results of a study by Irene Pepperberg suggested a high learning ability in an African Grey Parrot named Alex. Alex was trained to use words to identify objects, describe them, count them, and even answer complex questions such as "How many red squares?" with over 80% accuracy.

A second example is that of N'kisi, another African grey, which has been shown to have a vocabulary of approximately a thousand words and has displayed an ability to invent as well as use words in context and in the correct tense.

Parrots do not have vocal cords, so sound is accomplished by expelling air across the mouth of the bifurcated trachea. Different sounds are produced by changing the depth and shape of trachea.

African Grey Parrots of all subspecies are known for their superior ability to imitate sounds and human speech. This ability has made them prized as pets from ancient time to now. In the Masnavi, a writing by Rumi of Persia, AD 1250, the author talks about an ancient method for training parrots to speak.

Although most parrot species are able to imitate, some of the Amazon parrots are generally regarded as the next-best imitators and speakers of the parrot world. The question of why birds imitate remains open, but those that do often score very high on tests designed to measure problem solving ability.

Wild African Grey Parrots have been observed imitating other birds. Most other wild parrots have not been observed imitating other species.

Humans and parrots have a complicated relationship. Economically they can be beneficial to communities as sources of income from the pet trade and are highly marketable tourism draws and symbols. But some species are also economically important pests, particularly some cockatoo species in Australia.

Some parrots have also benefited from human changes to the environment in some instances, and have expanded their ranges where agricultural practices, and many parrots have declined as well. It is possible to devote careers to parrots. Zoos and aquariums employ keepers to care for and shape the behavior of parrots.

Some veterinarians who specialize in avian medicine will treat parrots exclusively. Biologists study parrot populations in the wild and help to conserve wild populations. Aviculturalists breed and sell parrots for the pet trade. As tens of millions parrots have been removed from the wild, and parrots have been traded in greater numbers and for far longer than any other group of wild animals.

Many parrot species are still threatened by this trade as well as habitat loss, predation by introduced species, and hunting for food or feathers. Some parrot species are agricultural pests,eating fruits, grains, and other crops, but parrots can also benefit economies through birdwatching based ecotourism.[