[ I or T ]（因惊讶、愤怒等）语无伦次地说;发出嘟囔声;发出噼啪声 to speak in a quick and confused way, producing short, unclear noises because of surprise, anger, etc.
[ + speech ] "But, er ... when, um, ... how?" he spluttered. “但是，呃……什么时候，嗯……怎样？”他语无伦次地说道。
The old gentleman was spluttering with indignation. 那位老先生愤怒地嘟囔着什么。
He sputtered an apology about being 14 minutes late.