The word "侃侃" is formed by reduplicating the character "侃", which itself is a phonetic-semantic compound composed of the radical "亻" (person) on the left, indicating human-related meaning, and the component on the right combining "口" (mouth) and "川" (river), suggesting continuous flow or speech. This structure conveys the idea of steady, frank expression, and when duplicated, "侃侃" functions as an adverb emphasizing confident, unrestrained speaking.