This has puzzled me for years. Parrots have no lips. Their tongues are shaped significantly differently from humans. Yet they can pronounce human sounds and words, including consonants such as P, B, T, L, and K. How is this possible? Or more to the point, how is it done?

i'm certainly no expert,but i'v had a couple macaws for over 30 years (yes they live that long and longer) they have thick tongues and are able to manipulate them very well, but the secret i think is their intelligence they are about on level of a 2-3 year old human (with both parents).
crows are also able to talk well if their tongue is split. also very intelligent birds