Final answer:
The lines praising Chanticleer's voice as merry as any angel's are spoken by The Nun's Priest in Geoffrey Chaucer's The Nun's Priest's Tale, part of The Canterbury Tales.
Step-by-step explanation:
The lines "as merry a voice as God has given/ To any angel in the courts of heaven" (lines 475-476) are spoken by The Nun's Priest in Geoffrey Chaucer's The Canterbury Tales, specifically in the tale known as The Nun's Priest's Tale. This statement is a compliment to Chanticleer, the rooster character in the tale, praising his singing voice. The Nun's Priest is the character who narrates the story of Chanticleer, Pertelote, and their adventures, including the encounter with the fox.