The word "嗫嚅" is formed from two characters, each incorporating the radical "口" (mouth) to indicate relation to speech. "嗫" combines "口" with "聂", which provides phonetic approximation and connotations of whispering, while "嚅" combines "口" with "需", offering phonetic cues and associations with hesitation. Together, they semantically compound to depict hesitant, stammering speech.