The word "唧唧喳喳" is formed through reduplication of the onomatopoeic characters "唧" and "喳", each repeated to mimic and intensify specific sounds: "唧" imitates light, sharp noises like chirping or whispering, and "喳" imitates louder, chaotic chattering, so the duplicated pair combines to create a compound representing continuous, overlapping sounds such as bird calls or noisy talk.