As our young chicks matured into young hens, they lost the cute 'peep' and replaced it with their mature adult voices. Most of our chickens make pleasant noises--small coos and clucks. Perhaps, the occasionally louder 'HEY!' at another chicken if they are upset.
But then, there is Angel. I've already described how Angel is a flat out bizarre chicken with a lot of personality. But one of her most defining characteristics is the way she vocalizes.
I'll be out in the garden, all will be quiet, and suddenly the peaceful scene is broken by a loud 'BAACCCHHHKK!!'. Or at least, that is how I guess you might spell Angel's language. She loves to make a lot of noise, and she really likes to talk to her human companions. If she can't see me, she makes much less noise. But if you're in view--she's going to let you know she's there!
I took this video of Angel talking. Enjoy!