inarticulate

他紧张得说不出话来，只能发出一些含糊不清的声音。

He was so nervous that he could only produce ___inarticulate sounds.

在面试中他紧张得说不出话来，只能支支吾吾地表达。

During the interview, he got so nervous that he became ___inarticulate and could only mumble.

他在演讲时紧张得说不出话来，只能发出断断续续的声音。

He was so nervous during the speech that he became ___inarticulate, only managing broken sounds.