The Chinese word "哈哈" is formed through the straightforward reduplication of the single character "哈", which phonetically mimics the sound of laughter. This doubling creates an onomatopoeic effect that vividly imitates the repetitive and hearty nature of laughing, emphasizing its auditory quality. Reduplication here serves as a simple morphological process to enhance expressiveness, directly echoing the actual sound it represents without relying on complex grammatical or lexical constructs.