Nowadays we say someone is 'speech-impaired', not dumb.

现在我们说某个人“有语言障碍”，而不说是哑巴。

《牛津词典》

"If they're not dumb," said Father, "who did it?"

“要是他们没装聋作哑，”父亲说，“那会是谁干的？”

youdao

The prisoners are, indeed, not dumb when it comes to shadows on the wall.

说到墙上的影子，囚徒们个个是这方面的专家。

youdao

But Marilyn was not happy. She was being asked to repeat her part as a dumb blonde in movie after movie.

VOA: special.2009.12.06

OK. Having said that, let's look at doing some sorts. And I'm going to start with a couple of dumb sorting mechanisms. Actually, that's the wrong way saying it, they're simply brain-damaged, they're not dumb, OK?

我们来做些排序吧,我要开始处理一些愚蠢的排序机制,事实上，我说的不正确，他们就是没脑子，不是笨,发明出来后，他们就在不停的被挑战？

麻省理工公开课 - 计算机科学及编程导论课程节选

Never mind, if you are doing that strategy, take it from a Brit, most princes are as dumb as toast, not worth waiting for.

如果你真的采取这个策略,记住这句英国的俗语吧,王子和土司一样蠢,不值得你去等的

耶鲁公开课 - 博弈论课程节选

"We're not dumb, " strategist and pollster Whit Ayres of Resurgent Republic told me.

BBC: Mitt Romney's dwindling 'diner' supporters

Maybe large Madison Avenue brands are not dumb, but smart.

FORBES: What if Mary Meeker is Wrong and Mobile Ads Never Really Take Off?

Individual investors are most definitely not dumb or stupid.

FORBES: Investors Are Not Dumb, Just Horrible At Market Timing