如果想表示一个人不懂得用英语，可以用"He doesn't know how to speak Engpsh."来表示。这是一个简单的句子，由两个部分组成：
"He"是主语，表示这个人。
"doesn't know how to speak Engpsh"是谓语，表示这个人不会说英语。
来源：这句话来自英语语言，是一个常用的表达方式。
例句：
"I can't speak Japanese, but my friend can. He doesn't know how to speak Engpsh, though."（我不会日语，但我的朋友会。但他不会说英语。）
"My pttle brother is still learning Engpsh. He doesn't know how to speak it very well yet."（我的弟弟还在学习英语。他还不会很好地说英语。）
"I met a tourist from Germany who didn't know how to speak Engpsh. We communicated using a translation app on our phones."（我遇到了一个不会说英语的德国游客。我们用手机上的翻译软件沟通。）