What causes difference in talking abilities between species?

I've been trying to find out whether The noted difference in talking abilities between species like Amazons and Greys to other species Is something that's physical (something with their syrinx, or is it something more to do with their minds?
(Not commenting on the intelligence of any particular species) Some may natually have sensitivity to sounds lile the components of human speech. The question is driving me nuts.

Well, from what I understand, there's a number of factors at play. There's physical limitations (lovebirds are incapable of producing the vocalizations necessary for human speech, parrotlets have very soft voices, etc.), the role vocalizations play in the wild (male budgies, for example, have complex ever-evolving songs to attract mates), the range of vocalizations in the wild (the more vocalizations a species has, the easier it is and the more likely it is for them to mimic human speech), whether the species is introverted or extroverted, etc. Parrots learn to speak human words for two reasons: (1) they think the words are cool and enjoy the challenge of learning, (2) they want to further connect with their human.

Well, the best talkers are, off the top of my head: budgies, eclectus, amazons, greys(?), and cockatoos. Hmm, let's think about what that means. Well, all of those species are extremely curious and thoughtful (i.e., they are all known for being nerds). They are all known for bonding extremely closely with their human (not that other species don't, but you guys know what I mean). Their social lives are extremely important to them (yes, I know, other species love their friends too), and they are nothing without their flock.

Like, budgies live in gigantic flocks, are communal nesters, and are unbelievably social. Eclectus, on the other hand, aren't exactly "flock" birds, but they are polygynandrous, meaning every female has multiple boyfriends, and every male has multiple girlfriends. While nesting, a single male will visit each of his girlfriends at their hollows to bring them food, and a nesting female will be visited daily by her various boyfriends to receive food (the females spend several months cooped up in her hollow, she depends on the boys to bring her food). Amazons...well I know nothing about those guys, so no comment, and the same goes for African greys. Cockatoos, like budgies, live in large flocks, are monogamous, and have tons of friends. Like, cockatoo couples will socialize with one another and talk about random things.

All of these species are very sensitive and are really in tune with one another's emotions. I guess you'd call it empathy. I know other species are really empathetic, but from what I understand about the top five talkers, these guys are extremely concerned about their friends. These species (with the exception of budgies) are notorious for self-harming, which is a pretty good indicator of intelligence and capacity to suffer.

We even have a member here who taught a sparrow to talk. Go figure. Some parrots talk, some dont, and the divide is not by species.

Interesting subject.
I would think that the ability to mimic is a survival characteristic so predators in the area they live would drive the species to develop flexibility in making sounds.

from what I can tell in regards to all avians and speech there are some more inclined to mimic human speech patterns, it is less intelligence based IMO but more to do with how much that bird mimics, for example you get many birds in cities now mimicking ringtones.

I believe as well there may be a slight point in the vocal chord structure of certain species. This is mere speculation but could it potentially be that some birds vocal chords such as Greys, Amazons, Macaws and 'Toos have a more similar vocal chord structure to us than the smaller birds? Which of course would make it easier to mimic our speech patterns