He does not speak standard Putonghua.

他的普通话说得不标准。

He speaks putonghua quite correctly.

他普通话说得很标准。

I'm stressed out because my Putonghua isn't improving.

我很容易紧张，因为普通话没有长进。

Putonghua test is a kind of standard referential test.

普通话水平测试属于标准参照性考试。

When you come into our school, you must speak Putonghua.

一进 学校，你就要讲普通话。