stammer

n. 结巴,口吃
v. 口吃,结巴
vi. 结结巴巴地说话,口吃
vt. 结结巴巴地说

He stammered his thanks.

他结结巴巴地道了谢。

The boy dare not answer the questions because of his stammer.

这个小男孩因为结巴不敢回答老师的问题。