stammer: implies a temporary inhibition of words from fear, embarrassment or shock: he ~ his thanks, overwhelmed by embarrassment.


stutter: is likely to suggest a habitual defect characterized by a repetition of sounds, BUT it may apply to similar manifestation due to a temporary cause: ~ when excited; or even, AS MAY stammer, to something suggesting the pattern of a stutterer: the engine ~ then came to life.


stammer: 表示暂时的不流畅(inhibition),由于害怕尴尬震惊等，stutter: 表示习惯性的缺陷，即发音重复(如把我说成"我我")，但也可表示暂时性的(缺陷)；还可表示像结巴的样子(pattern模式,指固定样子)，如例句中的发动机。



记忆方法: 1）Shi Sheng失声==>结巴。


         2）结巴的意思是讲话出错结巴mean to speak stumblingly. (stumble: 说话结巴出错: he stumbled over every sentence他每句都结结巴巴)