One of my neighbors is an old man who cannot speak.

我的一个邻居是个不会说话的老人。

youdao

I would like to learn Chinese because my parents are Chinese but I cannot speak Chinese!

我想学习汉语因为我的父母都是中国人但是我不会说汉语！

youdao

He said other things I cannot speak out for shame.

他还说了些我羞于启齿的话。

《新英汉大辞典》

Mr. HOAR: The obvious fact is, that someone that's on active duty cannot speak out and stay on.

NPR: Criticism of Rumsfeld Sparks Debate in Military

You cannot speak to anyone and no other prisoners can talk to you.

CNN: 'FRUSTRATIONS ARE HIGH'

By the time he dies of Creutzfeldt-Jakob disease he cannot speak or feed himself, or comprehend what has become of him.

ECONOMIST: The human brain