他一紧张说话就结巴，让人听不清楚。

tā yī jǐnzhāng shuōhuà jiù jiēba, ràng rén tīng bù qīngchǔ.

He stutters when he gets nervous, making it hard for people to understand.

别着急，慢慢说，你越急越结巴。

bié zhāojí, mànmàn shuō, nǐ yuè jí yuè jiēba.

Don't rush; speak slowly. The more anxious you get, the more you stutter.

小时候他有点结巴，长大以后好多了。

xiǎoshíhòu tā yǒudiǎn jiēba, zhǎngdà yǐhòu hǎo duō le.

He stuttered a little as a child, but it got much better when he grew up.