The word "啁啾" is formed as an onomatopoeic compound that mimics the sound of bird chirping. Each character is constructed phonosemantically: "啁" combines the mouth radical (口) to indicate sound-related meaning with the component "周" (zhōu) approximating its pronunciation, while "啾" similarly uses the mouth radical (口) with "秋" (qiū) for phonetic value. Together, these characters form a reduplicative pair that directly imitates avian vocalizations through their shared semantic and phonetic elements.