The word "磕磕巴巴" is formed by reduplicating the characters "磕" and "巴". "磕" conveys a sense of knocking or stumbling, while "巴" functions as a suffix in colloquial expressions. The repetition to "磕磕" and "巴巴" results in a compound that phonetically imitates and semantically describes stammering or disjointed speech, highlighting its faltering and irregular nature.