tā / yī / jǐnzhāng / jiù / shuō / de / diān / sān / dǎo / sì / dàjiā / dōu / tīng / bù / míngbai

他一紧张就说得颠三倒四，大家都听不明白。

Whenever he gets nervous, he speaks incoherently, and no one can understand him.