The Chinese word **唧唧 (jījī)** is a **reduplicative onomatopoeia**, formed by repeating the single syllable **唧 (jī)**, which itself is a phonetic character imitating a high-pitched, sharp sound. This morphological process, common in Chinese, uses repetition to create a vivid auditory depiction, and in this specific case, it conventionally represents the chirping or buzzing of insects (like crickets) or, in classical poetry, the sound of sighing. The reduplication intensifies and prolongs the sound, evoking a sense of continuity and atmosphere rather than denoting a concrete object or action.